15971138505 has 24 divisors (see below), whose sum is σ = 31638065472. Its totient is φ = 7301091744.

The previous prime is 15971138489. The next prime is 15971138549. The reversal of 15971138505 is 50583117951.

15971138505 is a `hidden beast` number, since 1 + 5 + 9 + 7 + 1 + 138 + 505 = 666.

It is not a de Polignac number, because 15971138505 - 2⁴ = 15971138489 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

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, 25350699 + ... + 25351328.

It is an arithmetic number, because the mean of its divisors is an integer number (1318252728).

Almost surely, 2^15971138505 is an apocalyptic number.

15971138505 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

15971138505 is a deficient number, since it is larger than the sum of its proper divisors (15666926967).

15971138505 is a wasteful number, since it uses less digits than its factorization.

15971138505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50702045 (or 50702042 counting only the distinct ones).

The product of its (nonzero) digits is 189000, while the sum is 45.

The spelling of 15971138505 in words is "fifteen billion, nine hundred seventy-one million, one hundred thirty-eight thousand, five hundred five".