21887690400 has 864 divisors, whose sum is σ = 87525023040. Its totient is φ = 5315051520.

The previous prime is 21887690389. The next prime is 21887690401. The reversal of 21887690400 is 409678812.

21887690400 is a `hidden beast` number, since 2 + 188 + 7 + 69 + 0 + 400 = 666.

It is a tau number, because it is divible by the number of its divisors (864).

It is a hoax number, since the sum of its digits (45) 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 (45).

It is not an unprimeable number, because it can be changed into a prime (21887690401) by changing a digit.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 122277511 + ... + 122277689.

It is an arithmetic number, because the mean of its divisors is an integer number (101302110).

Almost surely, 2^21887690400 is an apocalyptic number.

21887690400 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 21887690400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43762511520).

21887690400 is an abundant number, since it is smaller than the sum of its proper divisors (65637332640).

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

21887690400 is a wasteful number, since it uses less digits than its factorization.

21887690400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 268 (or 243 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 45.

The spelling of 21887690400 in words is "twenty-one billion, eight hundred eighty-seven million, six hundred ninety thousand, four hundred".