90521 has 4 divisors (see below), whose sum is σ = 91344. Its totient is φ = 89700.

The previous prime is 90511. The next prime is 90523. The reversal of 90521 is 12509.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 12509 = 7 ⋅1787.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-90521 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 90521.

It is not an unprimeable number, because it can be changed into a prime (90523) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 215 + ... + 476.

It is an arithmetic number, because the mean of its divisors is an integer number (22836).

2⁹⁰⁵²¹ is an apocalyptic number.

It is an amenable number.

90521 is a deficient number, since it is larger than the sum of its proper divisors (823).

90521 is a wasteful number, since it uses less digits than its factorization.

90521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 822.

The product of its (nonzero) digits is 90, while the sum is 17.

The square root of 90521 is about 300.8670802863. The cubic root of 90521 is about 44.9003556502.

The spelling of 90521 in words is "ninety thousand, five hundred twenty-one".