161520891 has 16 divisors (see below), whose sum is σ = 247382784. Its totient is φ = 91826784.

The previous prime is 161520847. The next prime is 161520899. The reversal of 161520891 is 198025161.

It is not a de Polignac number, because 161520891 - 2¹⁴ = 161504507 is a prime.

It is not an unprimeable number, because it can be changed into a prime (161520899) 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, 15385 + ... + 23658.

It is an arithmetic number, because the mean of its divisors is an integer number (15461424).

Almost surely, 2^161520891 is an apocalyptic number.

161520891 is a deficient number, since it is larger than the sum of its proper divisors (85861893).

161520891 is a wasteful number, since it uses less digits than its factorization.

161520891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39250.

The product of its (nonzero) digits is 4320, while the sum is 33.

The square root of 161520891 is about 12709.0869459611. The cubic root of 161520891 is about 544.5982405054.

The spelling of 161520891 in words is "one hundred sixty-one million, five hundred twenty thousand, eight hundred ninety-one".