65815988 has 24 divisors (see below), whose sum is σ = 134844864. Its totient is φ = 27518400.

The previous prime is 65815987. The next prime is 65815991. The reversal of 65815988 is 88951856.

It is a super-2 number, since 2×65815988² = 8663488552832288, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65815987) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27518 + ... + 29813.

It is an arithmetic number, because the mean of its divisors is an integer number (5618536).

Almost surely, 2^65815988 is an apocalyptic number.

It is an amenable number.

65815988 is an abundant number, since it is smaller than the sum of its proper divisors (69028876).

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

65815988 is a wasteful number, since it uses less digits than its factorization.

65815988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57383 (or 57381 counting only the distinct ones).

The product of its digits is 691200, while the sum is 50.

The square root of 65815988 is about 8112.7053440884. The cubic root of 65815988 is about 403.7480784094.

The spelling of 65815988 in words is "sixty-five million, eight hundred fifteen thousand, nine hundred eighty-eight".