91020661 has 2 divisors, whose sum is σ = 91020662. Its totient is φ = 91020660.

The previous prime is 91020653. The next prime is 91020689. The reversal of 91020661 is 16602019.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 58599025 + 32421636 = 7655^2 + 5694^2 .

It is a cyclic number.

It is not a de Polignac number, because 91020661 - 2³ = 91020653 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91020691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45510330 + 45510331.

It is an arithmetic number, because the mean of its divisors is an integer number (45510331).

Almost surely, 2^91020661 is an apocalyptic number.

It is an amenable number.

91020661 is a deficient number, since it is larger than the sum of its proper divisors (1).

91020661 is an equidigital number, since it uses as much as digits as its factorization.

91020661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 648, while the sum is 25.

The square root of 91020661 is about 9540.4748833588. The cubic root of 91020661 is about 449.8281829656.

The spelling of 91020661 in words is "ninety-one million, twenty thousand, six hundred sixty-one".