161797521 has 16 divisors (see below), whose sum is σ = 232626240. Its totient is φ = 99694080.

The previous prime is 161797507. The next prime is 161797553. The reversal of 161797521 is 125797161.

It is not a de Polignac number, because 161797521 - 2²² = 157603217 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 161797521.

It is not an unprimeable number, because it can be changed into a prime (161797591) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32280 + ... + 36953.

It is an arithmetic number, because the mean of its divisors is an integer number (14539140).

Almost surely, 2^161797521 is an apocalyptic number.

It is an amenable number.

161797521 is a deficient number, since it is larger than the sum of its proper divisors (70828719).

161797521 is a wasteful number, since it uses less digits than its factorization.

161797521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69296.

The product of its digits is 26460, while the sum is 39.

The square root of 161797521 is about 12719.9654480663. The cubic root of 161797521 is about 544.9089666430.

The spelling of 161797521 in words is "one hundred sixty-one million, seven hundred ninety-seven thousand, five hundred twenty-one".