421734646921 has 27 divisors (see below), whose sum is σ = 495572821653. Its totient is φ = 357851437440.

The previous prime is 421734646903. The next prime is 421734646939. The reversal of 421734646921 is 129646437124.

The square root of 421734646921 is 649411.

It is a perfect power (a square), and thus also a powerful number.

It is an interprime number because it is at equal distance from previous prime (421734646903) and next prime (421734646939).

It can be written as a sum of positive squares in 4 ways, for example, as 253769100025 + 167965546896 = 503755^2 + 409836^2 .

It is not a de Polignac number, because 421734646921 - 2²³ = 421726258313 is a prime.

It is a super-2 number, since 2×421734646921² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (49).

It is not an unprimeable number, because it can be changed into a prime (421734646321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 513683691 + ... + 513684511.

Almost surely, 2^421734646921 is an apocalyptic number.

421734646921 is the 649411-st square number.

421734646921 is the 324706-th centered octagonal number.

It is an amenable number.

421734646921 is a deficient number, since it is larger than the sum of its proper divisors (73838174732).

421734646921 is an frugal number, since it uses more digits than its factorization.

421734646921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1882 (or 941 counting only the distinct ones).

The product of its digits is 1741824, while the sum is 49.

Multiplying 421734646921 by its sum of digits (49), we get a square (20664997699129 = 4545877²).

421734646921 divided by its sum of digits (49) gives a square (8606829529 = 92773²).

The spelling of 421734646921 in words is "four hundred twenty-one billion, seven hundred thirty-four million, six hundred forty-six thousand, nine hundred twenty-one".