90205261 has 2 divisors, whose sum is σ = 90205262. Its totient is φ = 90205260.

The previous prime is 90205259. The next prime is 90205273. The reversal of 90205261 is 16250209.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 90060100 + 145161 = 9490^2 + 381^2 .

It is an emirp because it is prime and its reverse (16250209) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 90205261 - 2¹ = 90205259 is a prime.

It is a super-2 number, since 2×90205261² = 16273978224156242, which contains 22 as substring.

Together with 90205259, 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 (90200261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45102630 + 45102631.

It is an arithmetic number, because the mean of its divisors is an integer number (45102631).

Almost surely, 2^90205261 is an apocalyptic number.

It is an amenable number.

90205261 is a deficient number, since it is larger than the sum of its proper divisors (1).

90205261 is an equidigital number, since it uses as much as digits as its factorization.

90205261 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 90205261 is about 9497.6450238993. The cubic root of 90205261 is about 448.4809039908.

The spelling of 90205261 in words is "ninety million, two hundred five thousand, two hundred sixty-one".