172090621 has 2 divisors, whose sum is σ = 172090622. Its totient is φ = 172090620.

The previous prime is 172090613. The next prime is 172090627. The reversal of 172090621 is 126090271.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 116424100 + 55666521 = 10790^2 + 7461^2 .

It is an emirp because it is prime and its reverse (126090271) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 172090621 - 2³ = 172090613 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 172090621.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (172090627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 86045310 + 86045311.

It is an arithmetic number, because the mean of its divisors is an integer number (86045311).

Almost surely, 2^172090621 is an apocalyptic number.

It is an amenable number.

172090621 is a deficient number, since it is larger than the sum of its proper divisors (1).

172090621 is an equidigital number, since it uses as much as digits as its factorization.

172090621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1512, while the sum is 28.

The square root of 172090621 is about 13118.3314868927. The cubic root of 172090621 is about 556.2274281797.

The spelling of 172090621 in words is "one hundred seventy-two million, ninety thousand, six hundred twenty-one".