90405521 has 2 divisors, whose sum is σ = 90405522. Its totient is φ = 90405520.

The previous prime is 90405493. The next prime is 90405529. The reversal of 90405521 is 12550409.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 65044225 + 25361296 = 8065^2 + 5036^2 .

It is a cyclic number.

It is not a de Polignac number, because 90405521 - 2¹⁰ = 90404497 is a prime.

It is not a weakly prime, because it can be changed into another prime (90405529) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45202760 + 45202761.

It is an arithmetic number, because the mean of its divisors is an integer number (45202761).

Almost surely, 2^90405521 is an apocalyptic number.

It is an amenable number.

90405521 is a deficient number, since it is larger than the sum of its proper divisors (1).

90405521 is an equidigital number, since it uses as much as digits as its factorization.

90405521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1800, while the sum is 26.

The square root of 90405521 is about 9508.1817925406. The cubic root of 90405521 is about 448.8125417238.

The spelling of 90405521 in words is "ninety million, four hundred five thousand, five hundred twenty-one".