15501321261 has 24 divisors (see below), whose sum is σ = 22778159040. Its totient is φ = 10156825536.

The previous prime is 15501321257. The next prime is 15501321289. The reversal of 15501321261 is 16212310551.

15501321261 is a `hidden beast` number, since 1 + 5 + 501 + 32 + 126 + 1 = 666.

It is not a de Polignac number, because 15501321261 - 2² = 15501321257 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15501321961) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 75826 + ... + 191708.

It is an arithmetic number, because the mean of its divisors is an integer number (949089960).

Almost surely, 2^15501321261 is an apocalyptic number.

It is an amenable number.

15501321261 is a deficient number, since it is larger than the sum of its proper divisors (7276837779).

15501321261 is a wasteful number, since it uses less digits than its factorization.

15501321261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 116145 (or 116142 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 27.

The spelling of 15501321261 in words is "fifteen billion, five hundred one million, three hundred twenty-one thousand, two hundred sixty-one".