216156640 has 144 divisors (see below), whose sum is σ = 603288000. Its totient is φ = 72963072.

The previous prime is 216156623. The next prime is 216156697. The reversal of 216156640 is 46651612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 619186 + ... + 619534.

It is an arithmetic number, because the mean of its divisors is an integer number (4189500).

Almost surely, 2^216156640 is an apocalyptic number.

216156640 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 216156640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (301644000).

216156640 is an abundant number, since it is smaller than the sum of its proper divisors (387131360).

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

216156640 is a wasteful number, since it uses less digits than its factorization.

216156640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 457 (or 442 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 216156640 is about 14702.2664919393. The cubic root of 216156640 is about 600.1450019916.

The spelling of 216156640 in words is "two hundred sixteen million, one hundred fifty-six thousand, six hundred forty".