216864021540 has 96 divisors (see below), whose sum is σ = 611655367680. Its totient is φ = 57409191936.

The previous prime is 216864021497. The next prime is 216864021541. The reversal of 216864021540 is 45120468612.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (216864021541) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5527272 + ... + 5566368.

It is an arithmetic number, because the mean of its divisors is an integer number (6371410080).

Almost surely, 2^216864021540 is an apocalyptic number.

216864021540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

216864021540 is an abundant number, since it is smaller than the sum of its proper divisors (394791346140).

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

216864021540 is a wasteful number, since it uses less digits than its factorization.

216864021540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39781 (or 39779 counting only the distinct ones).

The product of its (nonzero) digits is 92160, while the sum is 39.

The spelling of 216864021540 in words is "two hundred sixteen billion, eight hundred sixty-four million, twenty-one thousand, five hundred forty".