21423298689 has 81 divisors (see below), whose sum is σ = 35047373283. Its totient is φ = 13088722608.

The previous prime is 21423298679. The next prime is 21423298717. The reversal of 21423298689 is 98689232412.

The square root of 21423298689 is 146367.

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

It can be written as a sum of positive squares in only one way, i.e., 3169127025 + 18254171664 = 56295^2 + 135108^2 .

It is a tau number, because it is divible by the number of its divisors (81).

It is not a de Polignac number, because 21423298689 - 2²¹ = 21421201537 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21423298609) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 154124382 + ... + 154124520.

Almost surely, 2^21423298689 is an apocalyptic number.

21423298689 is the 146367-th square number.

21423298689 is the 73184-th centered octagonal number.

It is an amenable number.

21423298689 is a deficient number, since it is larger than the sum of its proper divisors (13624074594).

21423298689 is an frugal number, since it uses more digits than its factorization.

21423298689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 328 (or 155 counting only the distinct ones).

The product of its digits is 2985984, while the sum is 54.

The spelling of 21423298689 in words is "twenty-one billion, four hundred twenty-three million, two hundred ninety-eight thousand, six hundred eighty-nine".