161651643 has 32 divisors (see below), whose sum is σ = 227852352. Its totient is φ = 101836800.

The previous prime is 161651627. The next prime is 161651669. The reversal of 161651643 is 346156161.

It is not a de Polignac number, because 161651643 - 2⁴ = 161651627 is a prime.

It is a super-2 number, since 2×161651643² = 52262507369198898, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (161651603) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 893013 + ... + 893193.

It is an arithmetic number, because the mean of its divisors is an integer number (7120386).

Almost surely, 2^161651643 is an apocalyptic number.

161651643 is a deficient number, since it is larger than the sum of its proper divisors (66200709).

161651643 is a wasteful number, since it uses less digits than its factorization.

161651643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 415.

The product of its digits is 12960, while the sum is 33.

The square root of 161651643 is about 12714.2299412902. The cubic root of 161651643 is about 544.7451525717.

The spelling of 161651643 in words is "one hundred sixty-one million, six hundred fifty-one thousand, six hundred forty-three".