21318920100 has 243 divisors, whose sum is σ = 69490683171. Its totient is φ = 5466614400.

The previous prime is 21318920093. The next prime is 21318920173. The reversal of 21318920100 is 102981312.

The square root of 21318920100 is 146010.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 2578405284 + 18740514816 = 50778^2 + 136896^2 .

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 135789222 + ... + 135789378.

Almost surely, 2^21318920100 is an apocalyptic number.

21318920100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

21318920100 is the 146010-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21318920100

21318920100 is an abundant number, since it is smaller than the sum of its proper divisors (48171763071).

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

21318920100 is a wasteful number, since it uses less digits than its factorization.

21318920100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 396 (or 198 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

It can be divided in two parts, 213189 and 20100, that added together give a square (233289 = 483²).

The spelling of 21318920100 in words is "twenty-one billion, three hundred eighteen million, nine hundred twenty thousand, one hundred".