21345025044 has 72 divisors (see below), whose sum is σ = 57955739520. Its totient is φ = 6096553344.

The previous prime is 21345025027. The next prime is 21345025061. The reversal of 21345025044 is 44052054312.

It is an interprime number because it is at equal distance from previous prime (21345025027) and next prime (21345025061).

It is a super-2 number, since 2×21345025044² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3430224 + ... + 3436440.

Almost surely, 2^21345025044 is an apocalyptic number.

It is an amenable number.

21345025044 is an abundant number, since it is smaller than the sum of its proper divisors (36610714476).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21345025044 is a wasteful number, since it uses less digits than its factorization.

21345025044 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12077 (or 12068 counting only the distinct ones).

The product of its (nonzero) digits is 19200, while the sum is 30.

Adding to 21345025044 its reverse (44052054312), we get a palindrome (65397079356).

The spelling of 21345025044 in words is "twenty-one billion, three hundred forty-five million, twenty-five thousand, forty-four".