90115661 has 2 divisors, whose sum is σ = 90115662. Its totient is φ = 90115660.

The previous prime is 90115643. The next prime is 90115693. The reversal of 90115661 is 16651109.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 82992100 + 7123561 = 9110^2 + 2669^2 .

It is a cyclic number.

It is not a de Polignac number, because 90115661 - 2¹⁴ = 90099277 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (90115601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45057830 + 45057831.

It is an arithmetic number, because the mean of its divisors is an integer number (45057831).

Almost surely, 2^90115661 is an apocalyptic number.

It is an amenable number.

90115661 is a deficient number, since it is larger than the sum of its proper divisors (1).

90115661 is an equidigital number, since it uses as much as digits as its factorization.

90115661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1620, while the sum is 29.

The square root of 90115661 is about 9492.9268932190. The cubic root of 90115661 is about 448.3323642395.

The spelling of 90115661 in words is "ninety million, one hundred fifteen thousand, six hundred sixty-one".