161253861 has 16 divisors (see below), whose sum is σ = 223278720. Its totient is φ = 103438080.

The previous prime is 161253803. The next prime is 161253871. The reversal of 161253861 is 168352161.

161253861 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

161253861 is a nontrivial binomial coefficient, being equal to C(17959, 2).

It is not a de Polignac number, because 161253861 - 2⁶ = 161253797 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161253871) 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, 1 + ... + 17958.

It is an arithmetic number, because the mean of its divisors is an integer number (13954920).

Almost surely, 2^161253861 is an apocalyptic number.

161253861 is the 17958-th triangular number.

It is an amenable number.

161253861 is a deficient number, since it is larger than the sum of its proper divisors (62024859).

161253861 is a wasteful number, since it uses less digits than its factorization.

161253861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18076.

The product of its digits is 8640, while the sum is 33.

The square root of 161253861 is about 12698.5771250168. The cubic root of 161253861 is about 544.2979609143.

The spelling of 161253861 in words is "one hundred sixty-one million, two hundred fifty-three thousand, eight hundred sixty-one".