161888431 has 4 divisors (see below), whose sum is σ = 166263832. Its totient is φ = 157513032.

The previous prime is 161888423. The next prime is 161888453. The reversal of 161888431 is 134888161.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 134888161 = 31 ⋅4351231.

It is a cyclic number.

It is not a de Polignac number, because 161888431 - 2³ = 161888423 is a prime.

It is a super-2 number, since 2×161888431² = 52415728183283522, 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 (161888401) 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, 2187645 + ... + 2187718.

It is an arithmetic number, because the mean of its divisors is an integer number (41565958).

Almost surely, 2^161888431 is an apocalyptic number.

161888431 is a deficient number, since it is larger than the sum of its proper divisors (4375401).

161888431 is an equidigital number, since it uses as much as digits as its factorization.

161888431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4375400.

The product of its digits is 36864, while the sum is 40.

The square root of 161888431 is about 12723.5384622360. The cubic root of 161888431 is about 545.0110044632.

The spelling of 161888431 in words is "one hundred sixty-one million, eight hundred eighty-eight thousand, four hundred thirty-one".