53999665 has 16 divisors (see below), whose sum is σ = 66716496. Its totient is φ = 41932800.

The previous prime is 53999657. The next prime is 53999681. The reversal of 53999665 is 56699935.

It can be written as a sum of positive squares in 8 ways, for example, as 665856 + 53333809 = 816^2 + 7303^2 .

It is not a de Polignac number, because 53999665 - 2³ = 53999657 is a prime.

It is a super-2 number, since 2×53999665² = 5831927640224450, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 48859 + ... + 49951.

It is an arithmetic number, because the mean of its divisors is an integer number (4169781).

Almost surely, 2^53999665 is an apocalyptic number.

It is an amenable number.

53999665 is a deficient number, since it is larger than the sum of its proper divisors (12716831).

53999665 is a wasteful number, since it uses less digits than its factorization.

53999665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1380.

The product of its digits is 1968300, while the sum is 52.

The square root of 53999665 is about 7348.4464344513. The cubic root of 53999665 is about 377.9755333492.

The spelling of 53999665 in words is "fifty-three million, nine hundred ninety-nine thousand, six hundred sixty-five".