21717372100 has 72 divisors (see below), whose sum is σ = 48797267400. Its totient is φ = 8379571200.

The previous prime is 21717372097. The next prime is 21717372101. The reversal of 21717372100 is 127371712.

It is a happy number.

It can be written as a sum of positive squares in 12 ways, for example, as 3356580096 + 18360792004 = 57936^2 + 135502^2 .

It is not an unprimeable number, because it can be changed into a prime (21717372101) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3828066 + ... + 3833734.

It is an arithmetic number, because the mean of its divisors is an integer number (677739825).

Almost surely, 2^21717372100 is an apocalyptic number.

21717372100 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 21717372100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24398633700).

21717372100 is an abundant number, since it is smaller than the sum of its proper divisors (27079895300).

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

21717372100 is a wasteful number, since it uses less digits than its factorization.

21717372100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7033 (or 7026 counting only the distinct ones).

The product of its (nonzero) digits is 4116, while the sum is 31.

The spelling of 21717372100 in words is "twenty-one billion, seven hundred seventeen million, three hundred seventy-two thousand, one hundred".