666406615 has 24 divisors (see below), whose sum is σ = 933774912. Its totient is φ = 455232960.

The previous prime is 666406583. The next prime is 666406621. The reversal of 666406615 is 516604666.

666406615 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 666406615 - 2⁵ = 666406583 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 61377 + ... + 71413.

It is an arithmetic number, because the mean of its divisors is an integer number (38907288).

Almost surely, 2^666406615 is an apocalyptic number.

666406615 is a deficient number, since it is larger than the sum of its proper divisors (267368297).

666406615 is a wasteful number, since it uses less digits than its factorization.

666406615 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10327 (or 10320 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 40.

The square root of 666406615 is about 25814.8526046538. The cubic root of 666406615 is about 873.4668619358.

The spelling of 666406615 in words is "six hundred sixty-six million, four hundred six thousand, six hundred fifteen".