661616005 has 16 divisors (see below), whose sum is σ = 864547200. Its totient is φ = 484142400.

The previous prime is 661615949. The next prime is 661616051. The reversal of 661616005 is 500616166.

It is not a de Polignac number, because 661616005 - 2¹¹ = 661613957 is a prime.

It is a congruent 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, 117321 + ... + 122830.

It is an arithmetic number, because the mean of its divisors is an integer number (54034200).

Almost surely, 2^661616005 is an apocalyptic number.

It is an amenable number.

661616005 is a deficient number, since it is larger than the sum of its proper divisors (202931195).

661616005 is a wasteful number, since it uses less digits than its factorization.

661616005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 240204.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 661616005 is about 25721.8973833580. The cubic root of 661616005 is about 871.3687904051.

The spelling of 661616005 in words is "six hundred sixty-one million, six hundred sixteen thousand, five".