90637021 has 2 divisors, whose sum is σ = 90637022. Its totient is φ = 90637020.

The previous prime is 90637003. The next prime is 90637051. The reversal of 90637021 is 12073609.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 84824100 + 5812921 = 9210^2 + 2411^2 .

It is an emirp because it is prime and its reverse (12073609) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 90637021 - 2⁵ = 90636989 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (90637051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45318510 + 45318511.

It is an arithmetic number, because the mean of its divisors is an integer number (45318511).

Almost surely, 2^90637021 is an apocalyptic number.

It is an amenable number.

90637021 is a deficient number, since it is larger than the sum of its proper divisors (1).

90637021 is an equidigital number, since it uses as much as digits as its factorization.

90637021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2268, while the sum is 28.

The square root of 90637021 is about 9520.3477352458. The cubic root of 90637021 is about 449.1953042774.

The spelling of 90637021 in words is "ninety million, six hundred thirty-seven thousand, twenty-one".