16172561 has 4 divisors (see below), whose sum is σ = 16300032. Its totient is φ = 16045092.

The previous prime is 16172557. The next prime is 16172581. The reversal of 16172561 is 16527161.

16172561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 16172561 - 2² = 16172557 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (16172501) 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, 63545 + ... + 63798.

It is an arithmetic number, because the mean of its divisors is an integer number (4075008).

Almost surely, 2^16172561 is an apocalyptic number.

It is an amenable number.

16172561 is a deficient number, since it is larger than the sum of its proper divisors (127471).

16172561 is a wasteful number, since it uses less digits than its factorization.

16172561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127470.

The product of its digits is 2520, while the sum is 29.

The square root of 16172561 is about 4021.5122777383. The cubic root of 16172561 is about 252.8868611494.

The spelling of 16172561 in words is "sixteen million, one hundred seventy-two thousand, five hundred sixty-one".