90911621 has 2 divisors, whose sum is σ = 90911622. Its totient is φ = 90911620.

The previous prime is 90911573. The next prime is 90911633. The reversal of 90911621 is 12611909.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 65044225 + 25867396 = 8065^2 + 5086^2 .

It is a cyclic number.

It is not a de Polignac number, because 90911621 - 2²² = 86717317 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (90911641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45455810 + 45455811.

It is an arithmetic number, because the mean of its divisors is an integer number (45455811).

Almost surely, 2^90911621 is an apocalyptic number.

It is an amenable number.

90911621 is a deficient number, since it is larger than the sum of its proper divisors (1).

90911621 is an equidigital number, since it uses as much as digits as its factorization.

90911621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 972, while the sum is 29.

The square root of 90911621 is about 9534.7585706194. The cubic root of 90911621 is about 449.6484843342.

The spelling of 90911621 in words is "ninety million, nine hundred eleven thousand, six hundred twenty-one".