21996100 has 81 divisors (see below), whose sum is σ = 56365533. Its totient is φ = 7428960.

The previous prime is 21996089. The next prime is 21996103. The reversal of 21996100 is 169912.

The square root of 21996100 is 4690.

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., 7918596 + 14077504 = 2814^2 + 3752^2 .

It is a Harshad number since it is a multiple of its sum of digits (28).

It is not an unprimeable number, because it can be changed into a prime (21996103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 328267 + ... + 328333.

Almost surely, 2^21996100 is an apocalyptic number.

21996100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

21996100 is the 4690-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21996100

21996100 is an abundant number, since it is smaller than the sum of its proper divisors (34369433).

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

21996100 is a wasteful number, since it uses less digits than its factorization.

21996100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 162 (or 81 counting only the distinct ones).

The product of its (nonzero) digits is 972, while the sum is 28.

The cubic root of 21996100 is about 280.1873745819.

The spelling of 21996100 in words is "twenty-one million, nine hundred ninety-six thousand, one hundred".