21764566400 has 96 divisors (see below), whose sum is σ = 53891230800. Its totient is φ = 8685434880.

The previous prime is 21764566399. The next prime is 21764566409. The reversal of 21764566400 is 466546712.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21764566409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1397054 + ... + 1412546.

Almost surely, 2^21764566400 is an apocalyptic number.

21764566400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21764566400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26945615400).

21764566400 is an abundant number, since it is smaller than the sum of its proper divisors (32126664400).

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

21764566400 is a wasteful number, since it uses less digits than its factorization.

21764566400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15956 (or 15939 counting only the distinct ones).

The product of its (nonzero) digits is 241920, while the sum is 41.

The spelling of 21764566400 in words is "twenty-one billion, seven hundred sixty-four million, five hundred sixty-six thousand, four hundred".