21378564900 has 720 divisors, whose sum is σ = 87356408832. Its totient is φ = 4393440000.

The previous prime is 21378564821. The next prime is 21378564919. The reversal of 21378564900 is 946587312.

21378564900 is a `hidden beast` number, since 2 + 13 + 78 + 564 + 9 + 0 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 239 ways as a sum of consecutive naturals, for example, 94178587 + ... + 94178813.

It is a 1-persistent number, because it is pandigital, but 2⋅21378564900 = 42757129800 is not.

Almost surely, 2^21378564900 is an apocalyptic number.

21378564900 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 21378564900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43678204416).

21378564900 is an abundant number, since it is smaller than the sum of its proper divisors (65977843932).

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

21378564900 is a wasteful number, since it uses less digits than its factorization.

21378564900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 422 (or 406 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 45.

The spelling of 21378564900 in words is "twenty-one billion, three hundred seventy-eight million, five hundred sixty-four thousand, nine hundred".