215815993600 has 81 divisors (see below), whose sum is σ = 534270309937. Its totient is φ = 86311531520.

The previous prime is 215815993583. The next prime is 215815993609. The reversal of 215815993600 is 6399518512.

The square root of 215815993600 is 464560.

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

It can be written as a sum of positive squares in only one way, i.e., 77693757696 + 138122235904 = 278736^2 + 371648^2 .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (215815993609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 37161897 + ... + 37167703.

Almost surely, 2^215815993600 is an apocalyptic number.

215815993600 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

215815993600 is the 464560-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 215815993600

215815993600 is an abundant number, since it is smaller than the sum of its proper divisors (318454316337).

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

215815993600 is an frugal number, since it uses more digits than its factorization.

215815993600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11640 (or 5814 counting only the distinct ones).

The product of its (nonzero) digits is 583200, while the sum is 49.

Multiplying 215815993600 by its sum of digits (49), we get a square (10574983686400 = 3251920²).

The spelling of 215815993600 in words is "two hundred fifteen billion, eight hundred fifteen million, nine hundred ninety-three thousand, six hundred".