215478851840 has 72 divisors (see below), whose sum is σ = 589873381440. Its totient is φ = 73878460416.

The previous prime is 215478851831. The next prime is 215478851921. The reversal of 215478851840 is 48158874512.

It is a happy number.

It is a super-2 number, since 2×215478851840² (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 7 ways as a sum of consecutive naturals, for example, 12015530 + ... + 12033449.

Almost surely, 2^215478851840 is an apocalyptic number.

215478851840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

215478851840 is an abundant number, since it is smaller than the sum of its proper divisors (374394529600).

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

215478851840 is an equidigital number, since it uses as much as digits as its factorization.

215478851840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24049007 (or 24048993 counting only the distinct ones).

The product of its (nonzero) digits is 2867200, while the sum is 53.

The spelling of 215478851840 in words is "two hundred fifteen billion, four hundred seventy-eight million, eight hundred fifty-one thousand, eight hundred forty".