161725251 has 8 divisors (see below), whose sum is σ = 218232000. Its totient is φ = 106517672.

The previous prime is 161725243. The next prime is 161725253. The reversal of 161725251 is 152527161.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 161725251 - 2³ = 161725243 is a prime.

It is a super-2 number, since 2×161725251² = 52310113622026002, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (161725253) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 324501 + ... + 324998.

It is an arithmetic number, because the mean of its divisors is an integer number (27279000).

Almost surely, 2^161725251 is an apocalyptic number.

161725251 is a deficient number, since it is larger than the sum of its proper divisors (56506749).

161725251 is an equidigital number, since it uses as much as digits as its factorization.

161725251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 649585.

The product of its digits is 4200, while the sum is 30.

The square root of 161725251 is about 12717.1243211663. The cubic root of 161725251 is about 544.8278231751.

The spelling of 161725251 in words is "one hundred sixty-one million, seven hundred twenty-five thousand, two hundred fifty-one".