161721475 has 12 divisors (see below), whose sum is σ = 200903560. Its totient is φ = 129139200.

The previous prime is 161721467. The next prime is 161721481. The reversal of 161721475 is 574127161.

It is not a de Polignac number, because 161721475 - 2³ = 161721467 is a prime.

It is a hoax number, since the sum of its digits (34) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 161721475.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 8611 + ... + 19939.

Almost surely, 2^161721475 is an apocalyptic number.

161721475 is a deficient number, since it is larger than the sum of its proper divisors (39182085).

161721475 is a wasteful number, since it uses less digits than its factorization.

161721475 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11910 (or 11905 counting only the distinct ones).

The product of its digits is 11760, while the sum is 34.

The square root of 161721475 is about 12716.9758590633. The cubic root of 161721475 is about 544.8235828852.

The spelling of 161721475 in words is "one hundred sixty-one million, seven hundred twenty-one thousand, four hundred seventy-five".