25535640666 has 16 divisors (see below), whose sum is σ = 51169313088. Its totient is φ = 8495541600.

The previous prime is 25535640659. The next prime is 25535640677. The reversal of 25535640666 is 66604653552.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4081270 + ... + 4087521.

It is an arithmetic number, because the mean of its divisors is an integer number (3198082068).

Almost surely, 2^25535640666 is an apocalyptic number.

25535640666 is an abundant number, since it is smaller than the sum of its proper divisors (25633672422).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

25535640666 is a wasteful number, since it uses less digits than its factorization.

25535640666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8169317.

The product of its (nonzero) digits is 3888000, while the sum is 48.

The spelling of 25535640666 in words is "twenty-five billion, five hundred thirty-five million, six hundred forty thousand, six hundred sixty-six".