21130023021 has 16 divisors (see below), whose sum is σ = 28507204800. Its totient is φ = 13919954048.

The previous prime is 21130022989. The next prime is 21130023029. The reversal of 21130023021 is 12032003112.

It is a cyclic number.

It is not a de Polignac number, because 21130023021 - 2⁵ = 21130022989 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21130023029) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 433150 + ... + 479456.

It is an arithmetic number, because the mean of its divisors is an integer number (1781700300).

Almost surely, 2^21130023021 is an apocalyptic number.

It is an amenable number.

21130023021 is a deficient number, since it is larger than the sum of its proper divisors (7377181779).

21130023021 is a wasteful number, since it uses less digits than its factorization.

21130023021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48108.

The product of its (nonzero) digits is 72, while the sum is 15.

Adding to 21130023021 its reverse (12032003112), we get a palindrome (33162026133).

The spelling of 21130023021 in words is "twenty-one billion, one hundred thirty million, twenty-three thousand, twenty-one".