90890921 has 4 divisors (see below), whose sum is σ = 99153744. Its totient is φ = 82628100.

The previous prime is 90890909. The next prime is 90890929. The reversal of 90890921 is 12909809.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-90890921 is a prime.

It is a super-2 number, since 2×90890921² = 16522319040456482, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (90890929) 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, 4131395 + ... + 4131416.

It is an arithmetic number, because the mean of its divisors is an integer number (24788436).

Almost surely, 2^90890921 is an apocalyptic number.

It is an amenable number.

90890921 is a deficient number, since it is larger than the sum of its proper divisors (8262823).

90890921 is a wasteful number, since it uses less digits than its factorization.

90890921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8262822.

The product of its (nonzero) digits is 11664, while the sum is 38.

The square root of 90890921 is about 9533.6730067692. The cubic root of 90890921 is about 449.6143543735.

The spelling of 90890921 in words is "ninety million, eight hundred ninety thousand, nine hundred twenty-one".