215661600000 has 1296 divisors, whose sum is σ = 971476571520. Its totient is φ = 44697600000.

The previous prime is 215661599981. The next prime is 215661600019. The reversal of 215661600000 is 6166512.

It is a happy number.

215661600000 is a `hidden beast` number, since 2 + 1 + 56 + 6 + 1 + 600 + 0 + 0 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (215661599981) and next prime (215661600019).

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, 554399806 + ... + 554400194.

It is an arithmetic number, because the mean of its divisors is an integer number (749596120).

Almost surely, 2^215661600000 is an apocalyptic number.

215661600000 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 215661600000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (485738285760).

215661600000 is an abundant number, since it is smaller than the sum of its proper divisors (755814971520).

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

215661600000 is an equidigital number, since it uses as much as digits as its factorization.

215661600000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 454 (or 417 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

Adding to 215661600000 its reverse (6166512), we get a palindrome (215667766512).

The spelling of 215661600000 in words is "two hundred fifteen billion, six hundred sixty-one million, six hundred thousand".