21716900 has 18 divisors (see below), whose sum is σ = 47125890. Its totient is φ = 8686720.

The previous prime is 21716887. The next prime is 21716927. The reversal of 21716900 is 961712.

21716900 = 920² + 921² + ... + 944².

It can be written as a sum of positive squares in 3 ways, for example, as 630436 + 21086464 = 794^2 + 4592^2 .

It is a super-2 number, since 2×21716900² = 943247491220000, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21716900.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 108485 + ... + 108684.

It is an arithmetic number, because the mean of its divisors is an integer number (2618105).

Almost surely, 2^21716900 is an apocalyptic number.

21716900 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21716900 is an abundant number, since it is smaller than the sum of its proper divisors (25408990).

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

21716900 is a wasteful number, since it uses less digits than its factorization.

21716900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 217183 (or 217176 counting only the distinct ones).

The product of its (nonzero) digits is 756, while the sum is 26.

The square root of 21716900 is about 4660.1394828910. The cubic root of 21716900 is about 278.9968353936.

The spelling of 21716900 in words is "twenty-one million, seven hundred sixteen thousand, nine hundred".