90172726181 has 2 divisors, whose sum is σ = 90172726182. Its totient is φ = 90172726180.

The previous prime is 90172726157. The next prime is 90172726243. The reversal of 90172726181 is 18162727109.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 83515798081 + 6656928100 = 288991^2 + 81590^2 .

It is an emirp because it is prime and its reverse (18162727109) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 90172726181 - 2²⁶ = 90105617317 is a prime.

It is a super-2 number, since 2×90172726181² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (90172726081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45086363090 + 45086363091.

It is an arithmetic number, because the mean of its divisors is an integer number (45086363091).

Almost surely, 2^90172726181 is an apocalyptic number.

It is an amenable number.

90172726181 is a deficient number, since it is larger than the sum of its proper divisors (1).

90172726181 is an equidigital number, since it uses as much as digits as its factorization.

90172726181 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 84672, while the sum is 44.

The spelling of 90172726181 in words is "ninety billion, one hundred seventy-two million, seven hundred twenty-six thousand, one hundred eighty-one".