21797569600 has 63 divisors (see below), whose sum is σ = 53650180101. Its totient is φ = 8716665600.

The previous prime is 21797569583. The next prime is 21797569603. The reversal of 21797569600 is 696579712.

It is a happy number.

The square root of 21797569600 is 147640.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 7847125056 + 13950444544 = 88584^2 + 118112^2 .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21797569603) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 5903755 + ... + 5907445.

Almost surely, 2^21797569600 is an apocalyptic number.

21797569600 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

21797569600 is the 147640-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21797569600

21797569600 is an abundant number, since it is smaller than the sum of its proper divisors (31852610501).

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

21797569600 is an frugal number, since it uses more digits than its factorization.

21797569600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7404 (or 3698 counting only the distinct ones).

The product of its (nonzero) digits is 1428840, while the sum is 52.

The spelling of 21797569600 in words is "twenty-one billion, seven hundred ninety-seven million, five hundred sixty-nine thousand, six hundred".