216637867520 has 80 divisors (see below), whose sum is σ = 520215387120. Its totient is φ = 86522978304.

The previous prime is 216637867483. The next prime is 216637867529. The reversal of 216637867520 is 25768736612.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×216637867520² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216637867529) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1622834 + ... + 1751246.

It is an arithmetic number, because the mean of its divisors is an integer number (6502692339).

Almost surely, 2^216637867520 is an apocalyptic number.

216637867520 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 216637867520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (260107693560).

216637867520 is an abundant number, since it is smaller than the sum of its proper divisors (303577519600).

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

216637867520 is an equidigital number, since it uses as much as digits as its factorization.

216637867520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129095 (or 129079 counting only the distinct ones).

The product of its (nonzero) digits is 5080320, while the sum is 53.

The spelling of 216637867520 in words is "two hundred sixteen billion, six hundred thirty-seven million, eight hundred sixty-seven thousand, five hundred twenty".