172285821 has 12 divisors (see below), whose sum is σ = 254645248. Its totient is φ = 112185864.

The previous prime is 172285793. The next prime is 172285823. The reversal of 172285821 is 128582271.

172285821 is a `hidden beast` number, since 1 + 72 + 2 + 8 + 582 + 1 = 666.

It is not a de Polignac number, because 172285821 - 2¹⁰ = 172284797 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (172285823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 222205 + ... + 222978.

Almost surely, 2^172285821 is an apocalyptic number.

It is an amenable number.

172285821 is a deficient number, since it is larger than the sum of its proper divisors (82359427).

172285821 is a wasteful number, since it uses less digits than its factorization.

172285821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 445232 (or 445229 counting only the distinct ones).

The product of its digits is 17920, while the sum is 36.

The square root of 172285821 is about 13125.7693488801. The cubic root of 172285821 is about 556.4376557278.

The spelling of 172285821 in words is "one hundred seventy-two million, two hundred eighty-five thousand, eight hundred twenty-one".