15581996137 has 4 divisors (see below), whose sum is σ = 15724950340. Its totient is φ = 15439041936.

The previous prime is 15581996117. The next prime is 15581996203. The reversal of 15581996137 is 73169918551.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 73169918551 = 3539 ⋅20675309.

It can be written as a sum of positive squares in 2 ways, for example, as 10476750736 + 5105245401 = 102356^2 + 71451^2 .

It is a cyclic number.

It is not a de Polignac number, because 15581996137 - 2²³ = 15573607529 is a prime.

It is a super-2 number, since 2×15581996137² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15581996107) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 71476938 + ... + 71477155.

It is an arithmetic number, because the mean of its divisors is an integer number (3931237585).

Almost surely, 2^15581996137 is an apocalyptic number.

It is an amenable number.

15581996137 is a deficient number, since it is larger than the sum of its proper divisors (142954203).

15581996137 is a wasteful number, since it uses less digits than its factorization.

15581996137 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 142954202.

The product of its digits is 2041200, while the sum is 55.

The spelling of 15581996137 in words is "fifteen billion, five hundred eighty-one million, nine hundred ninety-six thousand, one hundred thirty-seven".