90081557 has 2 divisors, whose sum is σ = 90081558. Its totient is φ = 90081556.

The previous prime is 90081533. The next prime is 90081559. The reversal of 90081557 is 75518009.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 74407876 + 15673681 = 8626^2 + 3959^2 .

It is a cyclic number.

It is not a de Polignac number, because 90081557 - 2⁶ = 90081493 is a prime.

It is a super-2 number, since 2×90081557² = 16229373823088498, which contains 22 as substring.

Together with 90081559, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (90081559) 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 as a sum of consecutive naturals, namely, 45040778 + 45040779.

It is an arithmetic number, because the mean of its divisors is an integer number (45040779).

Almost surely, 2^90081557 is an apocalyptic number.

It is an amenable number.

90081557 is a deficient number, since it is larger than the sum of its proper divisors (1).

90081557 is an equidigital number, since it uses as much as digits as its factorization.

90081557 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12600, while the sum is 35.

The square root of 90081557 is about 9491.1304384673. The cubic root of 90081557 is about 448.2758004266.

The spelling of 90081557 in words is "ninety million, eighty-one thousand, five hundred fifty-seven".