21409888464 has 80 divisors (see below), whose sum is σ = 63573460800. Its totient is φ = 6890534784.

The previous prime is 21409888459. The next prime is 21409888477. The reversal of 21409888464 is 46488890412.

It is a happy number.

21409888464 is a `hidden beast` number, since 2 + 14 + 0 + 98 + 88 + 464 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a self number, because there is not a number n which added to its sum of digits gives 21409888464.

It is a congruent number.

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, 841954 + ... + 867009.

It is an arithmetic number, because the mean of its divisors is an integer number (794668260).

Almost surely, 2^21409888464 is an apocalyptic number.

21409888464 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21409888464 is an abundant number, since it is smaller than the sum of its proper divisors (42163572336).

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

21409888464 is a wasteful number, since it uses less digits than its factorization.

21409888464 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1709009 (or 1708997 counting only the distinct ones).

The product of its (nonzero) digits is 3538944, while the sum is 54.

The spelling of 21409888464 in words is "twenty-one billion, four hundred nine million, eight hundred eighty-eight thousand, four hundred sixty-four".