216851640 has 32 divisors (see below), whose sum is σ = 650555280. Its totient is φ = 57827072.

The previous prime is 216851639. The next prime is 216851681. The reversal of 216851640 is 46158612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 903429 + ... + 903668.

Almost surely, 2^216851640 is an apocalyptic number.

216851640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

216851640 is an abundant number, since it is smaller than the sum of its proper divisors (433703640).

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

216851640 is a wasteful number, since it uses less digits than its factorization.

216851640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1807111 (or 1807107 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 33.

The square root of 216851640 is about 14725.8833351348. The cubic root of 216851640 is about 600.7875214533.

The spelling of 216851640 in words is "two hundred sixteen million, eight hundred fifty-one thousand, six hundred forty".