216761979 has 32 divisors (see below), whose sum is σ = 349009920. Its totient is φ = 117032832.

The previous prime is 216761977. The next prime is 216761981. The reversal of 216761979 is 979167612.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (216761977) and next prime (216761981).

It is not a de Polignac number, because 216761979 - 2¹ = 216761977 is a prime.

It is not an unprimeable number, because it can be changed into a prime (216761977) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 24837 + ... + 32409.

It is an arithmetic number, because the mean of its divisors is an integer number (10906560).

Almost surely, 2^216761979 is an apocalyptic number.

216761979 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

216761979 is a deficient number, since it is larger than the sum of its proper divisors (132247941).

216761979 is a wasteful number, since it uses less digits than its factorization.

216761979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7659.

The product of its digits is 285768, while the sum is 48.

The square root of 216761979 is about 14722.8386868837. The cubic root of 216761979 is about 600.7047080979.

It can be divided in two parts, 2167 and 61979, that added together give a palindrome (64146).

The spelling of 216761979 in words is "two hundred sixteen million, seven hundred sixty-one thousand, nine hundred seventy-nine".