161643461 has 4 divisors (see below), whose sum is σ = 184735392. Its totient is φ = 138551532.

The previous prime is 161643457. The next prime is 161643467. The reversal of 161643461 is 164346161.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 161643461 - 2² = 161643457 is a prime.

It is a super-2 number, since 2×161643461² = 52257216968117042, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161643467) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11545955 + ... + 11545968.

It is an arithmetic number, because the mean of its divisors is an integer number (46183848).

Almost surely, 2^161643461 is an apocalyptic number.

It is an amenable number.

161643461 is a deficient number, since it is larger than the sum of its proper divisors (23091931).

161643461 is an equidigital number, since it uses as much as digits as its factorization.

161643461 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23091930.

The product of its digits is 10368, while the sum is 32.

The square root of 161643461 is about 12713.9081717621. The cubic root of 161643461 is about 544.7359616557.

The spelling of 161643461 in words is "one hundred sixty-one million, six hundred forty-three thousand, four hundred sixty-one".