172039021 has 16 divisors (see below), whose sum is σ = 215003520. Its totient is φ = 133735680.

The previous prime is 172039019. The next prime is 172039051. The reversal of 172039021 is 120930271.

It is a cyclic number.

It is not a de Polignac number, because 172039021 - 2¹ = 172039019 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 (172039051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32745 + ... + 37633.

It is an arithmetic number, because the mean of its divisors is an integer number (13437720).

Almost surely, 2^172039021 is an apocalyptic number.

172039021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

172039021 is a deficient number, since it is larger than the sum of its proper divisors (42964499).

172039021 is a wasteful number, since it uses less digits than its factorization.

172039021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5364.

The product of its (nonzero) digits is 756, while the sum is 25.

The square root of 172039021 is about 13116.3646259167. The cubic root of 172039021 is about 556.1718291699.

Adding to 172039021 its reverse (120930271), we get a palindrome (292969292).

The spelling of 172039021 in words is "one hundred seventy-two million, thirty-nine thousand, twenty-one".