15500408661 has 12 divisors (see below), whose sum is σ = 22723651392. Its totient is φ = 10179372456.

The previous prime is 15500408659. The next prime is 15500408683. The reversal of 15500408661 is 16680400551.

15500408661 is a `hidden beast` number, since 1 + 550 + 0 + 40 + 8 + 6 + 61 = 666.

It is not a de Polignac number, because 15500408661 - 2¹ = 15500408659 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15500408641) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12852141 + ... + 12853346.

It is an arithmetic number, because the mean of its divisors is an integer number (1893637616).

Almost surely, 2^15500408661 is an apocalyptic number.

It is an amenable number.

15500408661 is a deficient number, since it is larger than the sum of its proper divisors (7223242731).

15500408661 is a wasteful number, since it uses less digits than its factorization.

15500408661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25705560 (or 25705557 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 36.

The spelling of 15500408661 in words is "fifteen billion, five hundred million, four hundred eight thousand, six hundred sixty-one".