21123310534 has 16 divisors (see below), whose sum is σ = 34428487680. Its totient is φ = 9683011080.

The previous prime is 21123310529. The next prime is 21123310541. The reversal of 21123310534 is 43501332112.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21123310499 and 21123310508.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8964574 + ... + 8966929.

It is an arithmetic number, because the mean of its divisors is an integer number (2151780480).

Almost surely, 2^21123310534 is an apocalyptic number.

21123310534 is a deficient number, since it is larger than the sum of its proper divisors (13305177146).

21123310534 is a wasteful number, since it uses less digits than its factorization.

21123310534 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17931555.

The product of its (nonzero) digits is 2160, while the sum is 25.

Adding to 21123310534 its reverse (43501332112), we get a palindrome (64624642646).

The spelling of 21123310534 in words is "twenty-one billion, one hundred twenty-three million, three hundred ten thousand, five hundred thirty-four".