90691789 has 2 divisors, whose sum is σ = 90691790. Its totient is φ = 90691788.

The previous prime is 90691781. The next prime is 90691793. The reversal of 90691789 is 98719609.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 78322500 + 12369289 = 8850^2 + 3517^2 .

It is a cyclic number.

It is not a de Polignac number, because 90691789 - 2³ = 90691781 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (90691781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45345894 + 45345895.

It is an arithmetic number, because the mean of its divisors is an integer number (45345895).

Almost surely, 2^90691789 is an apocalyptic number.

It is an amenable number.

90691789 is a deficient number, since it is larger than the sum of its proper divisors (1).

90691789 is an equidigital number, since it uses as much as digits as its factorization.

90691789 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 244944, while the sum is 49.

The square root of 90691789 is about 9523.2236663852. The cubic root of 90691789 is about 449.2857624390.

The spelling of 90691789 in words is "ninety million, six hundred ninety-one thousand, seven hundred eighty-nine".