661660615 has 16 divisors (see below), whose sum is σ = 989913600. Its totient is φ = 412463520.

The previous prime is 661660591. The next prime is 661660661. The reversal of 661660615 is 516066166.

661660615 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 661660615 - 2⁷ = 661660487 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, 858915 + ... + 859684.

It is an arithmetic number, because the mean of its divisors is an integer number (61869600).

Almost surely, 2^661660615 is an apocalyptic number.

661660615 is a deficient number, since it is larger than the sum of its proper divisors (328252985).

661660615 is a wasteful number, since it uses less digits than its factorization.

661660615 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1718622.

The product of its (nonzero) digits is 38880, while the sum is 37.

The square root of 661660615 is about 25722.7645287205. The cubic root of 661660615 is about 871.3883742160.

The spelling of 661660615 in words is "six hundred sixty-one million, six hundred sixty thousand, six hundred fifteen".