90419981 has 2 divisors, whose sum is σ = 90419982. Its totient is φ = 90419980.

The previous prime is 90419977. The next prime is 90420017. The reversal of 90419981 is 18991409.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 85285225 + 5134756 = 9235^2 + 2266^2 .

It is a cyclic number.

It is not a de Polignac number, because 90419981 - 2² = 90419977 is a prime.

It is a super-2 number, since 2×90419981² = 16351545928080722, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (90416981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45209990 + 45209991.

It is an arithmetic number, because the mean of its divisors is an integer number (45209991).

Almost surely, 2^90419981 is an apocalyptic number.

It is an amenable number.

90419981 is a deficient number, since it is larger than the sum of its proper divisors (1).

90419981 is an equidigital number, since it uses as much as digits as its factorization.

90419981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23328, while the sum is 41.

The square root of 90419981 is about 9508.9421598830. The cubic root of 90419981 is about 448.8364690360.

The spelling of 90419981 in words is "ninety million, four hundred nineteen thousand, nine hundred eighty-one".