663613665 has 96 divisors (see below), whose sum is σ = 1318052736. Its totient is φ = 281041920.

The previous prime is 663613607. The next prime is 663613721. The reversal of 663613665 is 566316366.

It is not a de Polignac number, because 663613665 - 2¹⁰ = 663612641 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 773917 + ... + 774773.

It is an arithmetic number, because the mean of its divisors is an integer number (13729716).

Almost surely, 2^663613665 is an apocalyptic number.

663613665 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

663613665 is a deficient number, since it is larger than the sum of its proper divisors (654439071).

663613665 is a wasteful number, since it uses less digits than its factorization.

663613665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 927 (or 908 counting only the distinct ones).

The product of its digits is 349920, while the sum is 42.

The square root of 663613665 is about 25760.7000098988. The cubic root of 663613665 is about 872.2449026127.

It can be divided in two parts, 6636 and 13665, that added together give a triangular number (20301 = T₂₀₁).

The spelling of 663613665 in words is "six hundred sixty-three million, six hundred thirteen thousand, six hundred sixty-five".