90238021 has 2 divisors, whose sum is σ = 90238022. Its totient is φ = 90238020.

The previous prime is 90238009. The next prime is 90238063. The reversal of 90238021 is 12083209.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 51624225 + 38613796 = 7185^2 + 6214^2 .

It is a cyclic number.

It is not a de Polignac number, because 90238021 - 2⁷ = 90237893 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (90238121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45119010 + 45119011.

It is an arithmetic number, because the mean of its divisors is an integer number (45119011).

Almost surely, 2^90238021 is an apocalyptic number.

It is an amenable number.

90238021 is a deficient number, since it is larger than the sum of its proper divisors (1).

90238021 is an equidigital number, since it uses as much as digits as its factorization.

90238021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 90238021 is about 9499.3695053935. The cubic root of 90238021 is about 448.5351892805.

The spelling of 90238021 in words is "ninety million, two hundred thirty-eight thousand, twenty-one".