21756004400 has 60 divisors (see below), whose sum is σ = 56289490992. Its totient is φ = 8032984320.

The previous prime is 21756004351. The next prime is 21756004411. The reversal of 21756004400 is 440065712.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2086724 + ... + 2097123.

Almost surely, 2^21756004400 is an apocalyptic number.

21756004400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21756004400 is an abundant number, since it is smaller than the sum of its proper divisors (34533486592).

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

21756004400 is a wasteful number, since it uses less digits than its factorization.

21756004400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4183878 (or 4183867 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 29.

The spelling of 21756004400 in words is "twenty-one billion, seven hundred fifty-six million, four thousand, four hundred".