21002521434 has 16 divisors (see below), whose sum is σ = 42247848672. Its totient is φ = 6960372848.

The previous prime is 21002521403. The next prime is 21002521439. The reversal of 21002521434 is 43412520012.

It is a super-2 number, since 2×21002521434² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21002521439) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10115784 + ... + 10117859.

It is an arithmetic number, because the mean of its divisors is an integer number (2640490542).

Almost surely, 2^21002521434 is an apocalyptic number.

21002521434 is an abundant number, since it is smaller than the sum of its proper divisors (21245327238).

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

21002521434 is a wasteful number, since it uses less digits than its factorization.

21002521434 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20233821.

The product of its (nonzero) digits is 1920, while the sum is 24.

The spelling of 21002521434 in words is "twenty-one billion, two million, five hundred twenty-one thousand, four hundred thirty-four".