161951566 has 32 divisors (see below), whose sum is σ = 289382400. Its totient is φ = 67917528.

The previous prime is 161951557. The next prime is 161951567. The reversal of 161951566 is 665159161.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161951567) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 29731 + ... + 34753.

It is an arithmetic number, because the mean of its divisors is an integer number (9043200).

Almost surely, 2^161951566 is an apocalyptic number.

161951566 is a deficient number, since it is larger than the sum of its proper divisors (127430834).

161951566 is an equidigital number, since it uses as much as digits as its factorization.

161951566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5093 (or 5079 counting only the distinct ones).

The product of its digits is 48600, while the sum is 40.

The square root of 161951566 is about 12726.0192519106. The cubic root of 161951566 is about 545.0818450155.

The spelling of 161951566 in words is "one hundred sixty-one million, nine hundred fifty-one thousand, five hundred sixty-six".