90521681 has 8 divisors (see below), whose sum is σ = 95514720. Its totient is φ = 85551552.

The previous prime is 90521659. The next prime is 90521687. The reversal of 90521681 is 18612509.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-90521681 is a prime.

It is a super-2 number, since 2×90521681² = 16388349462131522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (90521687) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2726 + ... + 13728.

It is an arithmetic number, because the mean of its divisors is an integer number (11939340).

Almost surely, 2^90521681 is an apocalyptic number.

It is an amenable number.

90521681 is a deficient number, since it is larger than the sum of its proper divisors (4993039).

90521681 is a wasteful number, since it uses less digits than its factorization.

90521681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11455.

The product of its (nonzero) digits is 4320, while the sum is 32.

The square root of 90521681 is about 9514.2882550404. The cubic root of 90521681 is about 449.0046824676.

The spelling of 90521681 in words is "ninety million, five hundred twenty-one thousand, six hundred eighty-one".