172121285 has 32 divisors (see below), whose sum is σ = 253808640. Its totient is φ = 109415232.

The previous prime is 172121273. The next prime is 172121291. The reversal of 172121285 is 582121271.

It is a cyclic number.

It is not a de Polignac number, because 172121285 - 2¹⁸ = 171859141 is a prime.

It is a super-6 number, since 6×172121285⁶ (a number of 51 digits) contains 666666 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 28502 + ... + 34008.

It is an arithmetic number, because the mean of its divisors is an integer number (7931520).

Almost surely, 2^172121285 is an apocalyptic number.

It is an amenable number.

172121285 is a deficient number, since it is larger than the sum of its proper divisors (81687355).

172121285 is a wasteful number, since it uses less digits than its factorization.

172121285 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5585.

The product of its digits is 2240, while the sum is 29.

The square root of 172121285 is about 13119.5001810282. The cubic root of 172121285 is about 556.2604633810.

It can be divided in two parts, 17212128 and 5, that multiplied together give a triangular number (86060640 = T₁₃₁₁₉).

The spelling of 172121285 in words is "one hundred seventy-two million, one hundred twenty-one thousand, two hundred eighty-five".