21365580600 has 576 divisors, whose sum is σ = 91600803840. Its totient is φ = 4506969600.

The previous prime is 21365580583. The next prime is 21365580619. The reversal of 21365580600 is 608556312.

21365580600 is a `hidden beast` number, since 2 + 13 + 6 + 5 + 580 + 60 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 4420185 + ... + 4425015.

Almost surely, 2^21365580600 is an apocalyptic number.

21365580600 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 21365580600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45800401920).

21365580600 is an abundant number, since it is smaller than the sum of its proper divisors (70235223240).

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

21365580600 is a wasteful number, since it uses less digits than its factorization.

21365580600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4882 (or 4861 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 36.

The spelling of 21365580600 in words is "twenty-one billion, three hundred sixty-five million, five hundred eighty thousand, six hundred".