161210251 has 4 divisors (see below), whose sum is σ = 163853104. Its totient is φ = 158567400.

The previous prime is 161210249. The next prime is 161210279. The reversal of 161210251 is 152012161.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 161210251 - 2¹ = 161210249 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161210051) 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, 1321335 + ... + 1321456.

It is an arithmetic number, because the mean of its divisors is an integer number (40963276).

Almost surely, 2^161210251 is an apocalyptic number.

161210251 is a deficient number, since it is larger than the sum of its proper divisors (2642853).

161210251 is an equidigital number, since it uses as much as digits as its factorization.

161210251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2642852.

The product of its (nonzero) digits is 120, while the sum is 19.

The square root of 161210251 is about 12696.8598873895. The cubic root of 161210251 is about 544.2488892744.

The spelling of 161210251 in words is "one hundred sixty-one million, two hundred ten thousand, two hundred fifty-one".