216997690 has 128 divisors (see below), whose sum is σ = 518192640. Its totient is φ = 63857664.

The previous prime is 216997687. The next prime is 216997717. The reversal of 216997690 is 96799612.

It is a super-2 number, since 2×216997690² = 94175994930672200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2614389 + ... + 2614471.

It is an arithmetic number, because the mean of its divisors is an integer number (4048380).

Almost surely, 2^216997690 is an apocalyptic number.

216997690 is an abundant number, since it is smaller than the sum of its proper divisors (301194950).

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

216997690 is a wasteful number, since it uses less digits than its factorization.

216997690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 153 (or 127 counting only the distinct ones).

The product of its (nonzero) digits is 367416, while the sum is 49.

The square root of 216997690 is about 14730.8414559386. The cubic root of 216997690 is about 600.9223683714.

The spelling of 216997690 in words is "two hundred sixteen million, nine hundred ninety-seven thousand, six hundred ninety".