21156045600 has 144 divisors (see below), whose sum is σ = 69085390752. Its totient is φ = 5623388160.

The previous prime is 21156045571. The next prime is 21156045649. The reversal of 21156045600 is 654065112.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 737119 + ... + 765281.

It is an arithmetic number, because the mean of its divisors is an integer number (479759658).

Almost surely, 2^21156045600 is an apocalyptic number.

21156045600 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 21156045600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34542695376).

21156045600 is an abundant number, since it is smaller than the sum of its proper divisors (47929345152).

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

21156045600 is a wasteful number, since it uses less digits than its factorization.

21156045600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28499 (or 28486 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 30.

The spelling of 21156045600 in words is "twenty-one billion, one hundred fifty-six million, forty-five thousand, six hundred".