161691526506 has 8 divisors (see below), whose sum is σ = 323383053024. Its totient is φ = 53897175500.

The previous prime is 161691526463. The next prime is 161691526541. The reversal of 161691526506 is 605625196161.

It is a sphenic number, since it is the product of 3 distinct primes.

161691526506 is an admirable number.

It is a super-2 number, since 2×161691526506² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13474293870 + ... + 13474293881.

It is an arithmetic number, because the mean of its divisors is an integer number (40422881628).

Almost surely, 2^161691526506 is an apocalyptic number.

161691526506 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161691526506 is a wasteful number, since it uses less digits than its factorization.

161691526506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26948587756.

The product of its (nonzero) digits is 583200, while the sum is 48.

The spelling of 161691526506 in words is "one hundred sixty-one billion, six hundred ninety-one million, five hundred twenty-six thousand, five hundred six".