65661816 has 32 divisors (see below), whose sum is σ = 179078400. Its totient is φ = 19897440.

The previous prime is 65661737. The next prime is 65661833. The reversal of 65661816 is 61816656.

It is a super-2 number, since 2×65661816² = 8622948160835712, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 124096 + ... + 124623.

It is an arithmetic number, because the mean of its divisors is an integer number (5596200).

Almost surely, 2^65661816 is an apocalyptic number.

65661816 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is an amenable number.

65661816 is an abundant number, since it is smaller than the sum of its proper divisors (113416584).

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

65661816 is a wasteful number, since it uses less digits than its factorization.

65661816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 248739 (or 248735 counting only the distinct ones).

The product of its digits is 51840, while the sum is 39.

The square root of 65661816 is about 8103.1978872541. The cubic root of 65661816 is about 403.4325759627.

The spelling of 65661816 in words is "sixty-five million, six hundred sixty-one thousand, eight hundred sixteen".