21716800 has 126 divisors (see below), whose sum is σ = 62385702. Its totient is φ = 7418880.

The previous prime is 21716767. The next prime is 21716809. The reversal of 21716800 is 861712.

It can be written as a sum of positive squares in 3 ways, for example, as 112896 + 21603904 = 336^2 + 4648^2 .

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21716809) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 78262 + ... + 78538.

Almost surely, 2^21716800 is an apocalyptic number.

21716800 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 21716800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31192851).

21716800 is an abundant number, since it is smaller than the sum of its proper divisors (40668902).

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

21716800 is a wasteful number, since it uses less digits than its factorization.

21716800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 313 (or 291 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 25.

The square root of 21716800 is about 4660.1287535861. The cubic root of 21716800 is about 278.9964071599.

The spelling of 21716800 in words is "twenty-one million, seven hundred sixteen thousand, eight hundred".