161581926586 has 4 divisors (see below), whose sum is σ = 242372889882. Its totient is φ = 80790963292.

The previous prime is 161581926563. The next prime is 161581926599. The reversal of 161581926586 is 685629185161.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 151452510561 + 10129416025 = 389169^2 + 100645^2 .

It is a super-2 number, since 2×161581926586² (a number of 23 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (58) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 161581926586.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40395481645 + ... + 40395481648.

Almost surely, 2^161581926586 is an apocalyptic number.

161581926586 is a deficient number, since it is larger than the sum of its proper divisors (80790963296).

161581926586 is an equidigital number, since it uses as much as digits as its factorization.

161581926586 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80790963295.

The product of its digits is 6220800, while the sum is 58.

The spelling of 161581926586 in words is "one hundred sixty-one billion, five hundred eighty-one million, nine hundred twenty-six thousand, five hundred eighty-six".