215681665584 has 240 divisors, whose sum is σ = 716208770816. Its totient is φ = 54717949440.

The previous prime is 215681665547. The next prime is 215681665621. The reversal of 215681665584 is 485566186512.

215681665584 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (215681665547) and next prime (215681665621).

It is a super-2 number, since 2×215681665584² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1686522 + ... + 1809894.

Almost surely, 2^215681665584 is an apocalyptic number.

215681665584 is a gapful number since it is divisible by the number (24) 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 215681665584, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (358104385408).

215681665584 is an abundant number, since it is smaller than the sum of its proper divisors (500527105232).

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

215681665584 is a wasteful number, since it uses less digits than its factorization.

215681665584 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123456 (or 123439 counting only the distinct ones).

The product of its digits is 13824000, while the sum is 57.

The spelling of 215681665584 in words is "two hundred fifteen billion, six hundred eighty-one million, six hundred sixty-five thousand, five hundred eighty-four".