21012400074 has 32 divisors (see below), whose sum is σ = 42929300736. Its totient is φ = 6853455360.

The previous prime is 21012400021. The next prime is 21012400111. The reversal of 21012400074 is 47000421012.

It is a happy number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21012400074.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1821894 + ... + 1833390.

It is an arithmetic number, because the mean of its divisors is an integer number (1341540648).

Almost surely, 2^21012400074 is an apocalyptic number.

21012400074 is an abundant number, since it is smaller than the sum of its proper divisors (21916900662).

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

21012400074 is a wasteful number, since it uses less digits than its factorization.

21012400074 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18030.

The product of its (nonzero) digits is 448, while the sum is 21.

Adding to 21012400074 its reverse (47000421012), we get a palindrome (68012821086).

The spelling of 21012400074 in words is "twenty-one billion, twelve million, four hundred thousand, seventy-four".