172361521 has 16 divisors (see below), whose sum is σ = 192931200. Its totient is φ = 153024768.

The previous prime is 172361509. The next prime is 172361533. The reversal of 172361521 is 125163271.

172361521 = T₁₀₇₁₈ + T₁₀₇₁₉ + T₁₀₇₂₀.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (172361509) and next prime (172361533).

It is a cyclic number.

It is not a de Polignac number, because 172361521 - 2⁷ = 172361393 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 172361521.

It is not an unprimeable number, because it can be changed into a prime (172361551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 83935 + ... + 85963.

It is an arithmetic number, because the mean of its divisors is an integer number (12058200).

Almost surely, 2^172361521 is an apocalyptic number.

172361521 is the 10720-th centered triangular number.

It is an amenable number.

172361521 is a deficient number, since it is larger than the sum of its proper divisors (20569679).

172361521 is a wasteful number, since it uses less digits than its factorization.

172361521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2328.

The product of its digits is 2520, while the sum is 28.

The square root of 172361521 is about 13128.6526726850. The cubic root of 172361521 is about 556.5191407904.

The spelling of 172361521 in words is "one hundred seventy-two million, three hundred sixty-one thousand, five hundred twenty-one".