53981665 has 4 divisors (see below), whose sum is σ = 64778004. Its totient is φ = 43185328.

The previous prime is 53981651. The next prime is 53981687. The reversal of 53981665 is 56618935.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 56618935 = 5 ⋅11323787.

It can be written as a sum of positive squares in 2 ways, for example, as 6330256 + 47651409 = 2516^2 + 6903^2 .

It is a cyclic number.

It is not a de Polignac number, because 53981665 - 2²³ = 45593057 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5398162 + ... + 5398171.

It is an arithmetic number, because the mean of its divisors is an integer number (16194501).

Almost surely, 2^53981665 is an apocalyptic number.

It is an amenable number.

53981665 is a deficient number, since it is larger than the sum of its proper divisors (10796339).

53981665 is a wasteful number, since it uses less digits than its factorization.

53981665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10796338.

The product of its digits is 194400, while the sum is 43.

The square root of 53981665 is about 7347.2215837009. The cubic root of 53981665 is about 377.9335311398.

The spelling of 53981665 in words is "fifty-three million, nine hundred eighty-one thousand, six hundred sixty-five".