21996900 has 72 divisors (see below), whose sum is σ = 70724640. Its totient is φ = 5865120.

The previous prime is 21996899. The next prime is 21996913. The reversal of 21996900 is 969912.

It is a super-2 number, since 2×21996900² = 967727219220000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 1374 + ... + 6773.

Almost surely, 2^21996900 is an apocalyptic number.

21996900 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 21996900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35362320).

21996900 is an abundant number, since it is smaller than the sum of its proper divisors (48727740).

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

21996900 is a wasteful number, since it uses less digits than its factorization.

21996900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8170 (or 8157 counting only the distinct ones).

The product of its (nonzero) digits is 8748, while the sum is 36.

The square root of 21996900 is about 4690.0852870710. The cubic root of 21996900 is about 280.1907713535.

The spelling of 21996900 in words is "twenty-one million, nine hundred ninety-six thousand, nine hundred".