172212491 has 4 divisors (see below), whose sum is σ = 187868184. Its totient is φ = 156556800.

The previous prime is 172212473. The next prime is 172212497. The reversal of 172212491 is 194212271.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 194212271 = 11 ⋅17655661.

It is a cyclic number.

It is not a de Polignac number, because 172212491 - 2¹⁸ = 171950347 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (172212497) 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 3 ways as a sum of consecutive naturals, for example, 7827830 + ... + 7827851.

It is an arithmetic number, because the mean of its divisors is an integer number (46967046).

Almost surely, 2^172212491 is an apocalyptic number.

172212491 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

172212491 is a deficient number, since it is larger than the sum of its proper divisors (15655693).

172212491 is a wasteful number, since it uses less digits than its factorization.

172212491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15655692.

The product of its digits is 2016, while the sum is 29.

The square root of 172212491 is about 13122.9756915114. The cubic root of 172212491 is about 556.3586990199.

The spelling of 172212491 in words is "one hundred seventy-two million, two hundred twelve thousand, four hundred ninety-one".