21421370493 has 6 divisors (see below), whose sum is σ = 30941979614. Its totient is φ = 14280913656.

The previous prime is 21421370473. The next prime is 21421370533. The reversal of 21421370493 is 39407312412.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 13769144964 + 7652225529 = 117342^2 + 87477^2 .

It is not a de Polignac number, because 21421370493 - 2⁶ = 21421370429 is a prime.

It is a super-2 number, since 2×21421370493² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21421370423) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1190076130 + ... + 1190076147.

Almost surely, 2^21421370493 is an apocalyptic number.

It is an amenable number.

21421370493 is a deficient number, since it is larger than the sum of its proper divisors (9520609121).

21421370493 is a wasteful number, since it uses less digits than its factorization.

21421370493 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2380152283 (or 2380152280 counting only the distinct ones).

The product of its (nonzero) digits is 36288, while the sum is 36.

The spelling of 21421370493 in words is "twenty-one billion, four hundred twenty-one million, three hundred seventy thousand, four hundred ninety-three".