90745021 has 2 divisors, whose sum is σ = 90745022. Its totient is φ = 90745020.

The previous prime is 90745019. The next prime is 90745037. The reversal of 90745021 is 12054709.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 46376100 + 44368921 = 6810^2 + 6661^2 .

It is a cyclic number.

It is not a de Polignac number, because 90745021 - 2¹ = 90745019 is a prime.

Together with 90745019, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (90742021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45372510 + 45372511.

It is an arithmetic number, because the mean of its divisors is an integer number (45372511).

Almost surely, 2^90745021 is an apocalyptic number.

It is an amenable number.

90745021 is a deficient number, since it is larger than the sum of its proper divisors (1).

90745021 is an equidigital number, since it uses as much as digits as its factorization.

90745021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 90745021 is about 9526.0181083179. The cubic root of 90745021 is about 449.3736487560.

The spelling of 90745021 in words is "ninety million, seven hundred forty-five thousand, twenty-one".