216640660400 has 240 divisors, whose sum is σ = 565270963200. Its totient is φ = 79588992000.

The previous prime is 216640660387. The next prime is 216640660421. The reversal of 216640660400 is 4066046612.

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, 21211295 + ... + 21221505.

It is an arithmetic number, because the mean of its divisors is an integer number (2355295680).

Almost surely, 2^216640660400 is an apocalyptic number.

216640660400 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 216640660400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (282635481600).

216640660400 is an abundant number, since it is smaller than the sum of its proper divisors (348630302800).

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

216640660400 is a wasteful number, since it uses less digits than its factorization.

216640660400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10348 (or 10337 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 35.

The spelling of 216640660400 in words is "two hundred sixteen billion, six hundred forty million, six hundred sixty thousand, four hundred".