215856017640 has 128 divisors (see below), whose sum is σ = 731315692800. Its totient is φ = 56617954560.

The previous prime is 215856017639. The next prime is 215856017653. The reversal of 215856017640 is 46710658512.

215856017640 is a `hidden beast` number, since 2 + 1 + 585 + 6 + 0 + 1 + 7 + 64 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1572372 + ... + 1704131.

It is an arithmetic number, because the mean of its divisors is an integer number (5713403850).

Almost surely, 2^215856017640 is an apocalyptic number.

215856017640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

215856017640 is an abundant number, since it is smaller than the sum of its proper divisors (515459675160).

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

215856017640 is a wasteful number, since it uses less digits than its factorization.

215856017640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3276584 (or 3276574 counting only the distinct ones).

The product of its (nonzero) digits is 403200, while the sum is 45.

The spelling of 215856017640 in words is "two hundred fifteen billion, eight hundred fifty-six million, seventeen thousand, six hundred forty".