90607721 has 2 divisors, whose sum is σ = 90607722. Its totient is φ = 90607720.

The previous prime is 90607703. The next prime is 90607723. The reversal of 90607721 is 12770609.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 76650025 + 13957696 = 8755^2 + 3736^2 .

It is a cyclic number.

It is not a de Polignac number, because 90607721 - 2¹⁰ = 90606697 is a prime.

Together with 90607723, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (90607723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45303860 + 45303861.

It is an arithmetic number, because the mean of its divisors is an integer number (45303861).

Almost surely, 2^90607721 is an apocalyptic number.

It is an amenable number.

90607721 is a deficient number, since it is larger than the sum of its proper divisors (1).

90607721 is an equidigital number, since it uses as much as digits as its factorization.

90607721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5292, while the sum is 32.

The square root of 90607721 is about 9518.8088015255. The cubic root of 90607721 is about 449.1468956517.

The spelling of 90607721 in words is "ninety million, six hundred seven thousand, seven hundred twenty-one".