21864600 has 96 divisors (see below), whose sum is σ = 75330000. Its totient is φ = 5829120.

The previous prime is 21864587. The next prime is 21864613. The reversal of 21864600 is 646812.

21864600 is a `hidden beast` number, since 2 + 18 + 646 + 0 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (21864587) and next prime (21864613).

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3376 + ... + 7424.

Almost surely, 2^21864600 is an apocalyptic number.

21864600 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

21864600 is the 2700-th octagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21864600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37665000).

21864600 is an abundant number, since it is smaller than the sum of its proper divisors (53465400).

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

21864600 is a wasteful number, since it uses less digits than its factorization.

21864600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4074 (or 4059 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 21864600 is about 4675.9597945235. The cubic root of 21864600 is about 279.6279071041.

It can be divided in two parts, 2186 and 4600, that added together give a triangular number (6786 = T₁₁₆).

The spelling of 21864600 in words is "twenty-one million, eight hundred sixty-four thousand, six hundred".