216997988 has 24 divisors (see below), whose sum is σ = 388620960. Its totient is φ = 105986880.

The previous prime is 216997987. The next prime is 216997997. The reversal of 216997988 is 889799612.

It is a Harshad number since it is a multiple of its sum of digits (59).

It is not an unprimeable number, because it can be changed into a prime (216997987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 35648 + ... + 41288.

It is an arithmetic number, because the mean of its divisors is an integer number (16192540).

Almost surely, 2^216997988 is an apocalyptic number.

It is an amenable number.

216997988 is a deficient number, since it is larger than the sum of its proper divisors (171622972).

216997988 is a wasteful number, since it uses less digits than its factorization.

216997988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5867 (or 5865 counting only the distinct ones).

The product of its digits is 3919104, while the sum is 59.

The square root of 216997988 is about 14730.8515707681. The cubic root of 216997988 is about 600.9226434508.

The spelling of 216997988 in words is "two hundred sixteen million, nine hundred ninety-seven thousand, nine hundred eighty-eight".