21146344840 has 16 divisors (see below), whose sum is σ = 47579275980. Its totient is φ = 8458537920.

The previous prime is 21146344819. The next prime is 21146344859. The reversal of 21146344840 is 4844364112.

It can be written as a sum of positive squares in 2 ways, for example, as 19700368164 + 1445976676 = 140358^2 + 38026^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21146344840.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 264329271 + ... + 264329350.

Almost surely, 2^21146344840 is an apocalyptic number.

21146344840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21146344840 is an abundant number, since it is smaller than the sum of its proper divisors (26432931140).

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

21146344840 is a wasteful number, since it uses less digits than its factorization.

21146344840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 528658632 (or 528658628 counting only the distinct ones).

The product of its (nonzero) digits is 73728, while the sum is 37.

The spelling of 21146344840 in words is "twenty-one billion, one hundred forty-six million, three hundred forty-four thousand, eight hundred forty".