216739957 has 4 divisors (see below), whose sum is σ = 247702816. Its totient is φ = 185777100.

The previous prime is 216739951. The next prime is 216739961. The reversal of 216739957 is 759937612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 216739957 - 2⁷ = 216739829 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 216739957.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216739951) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15481419 + ... + 15481432.

It is an arithmetic number, because the mean of its divisors is an integer number (61925704).

Almost surely, 2^216739957 is an apocalyptic number.

It is an amenable number.

216739957 is a deficient number, since it is larger than the sum of its proper divisors (30962859).

216739957 is an equidigital number, since it uses as much as digits as its factorization.

216739957 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30962858.

The product of its digits is 714420, while the sum is 49.

The square root of 216739957 is about 14722.0907822225. The cubic root of 216739957 is about 600.6843644823.

It can be divided in two parts, 2167 and 39957, that added together give a palindrome (42124).

The spelling of 216739957 in words is "two hundred sixteen million, seven hundred thirty-nine thousand, nine hundred fifty-seven".