90723921 has 4 divisors (see below), whose sum is σ = 120965232. Its totient is φ = 60482612.

The previous prime is 90723911. The next prime is 90723923. The reversal of 90723921 is 12932709.

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 not a de Polignac number, because 90723921 - 2⁷ = 90723793 is a prime.

It is a super-2 number, since 2×90723921² = 16461659683228482, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (90723923) 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, 15120651 + ... + 15120656.

It is an arithmetic number, because the mean of its divisors is an integer number (30241308).

Almost surely, 2^90723921 is an apocalyptic number.

It is an amenable number.

90723921 is a deficient number, since it is larger than the sum of its proper divisors (30241311).

90723921 is a wasteful number, since it uses less digits than its factorization.

90723921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30241310.

The product of its (nonzero) digits is 6804, while the sum is 33.

The square root of 90723921 is about 9524.9105507611. The cubic root of 90723921 is about 449.3388166559.

The spelling of 90723921 in words is "ninety million, seven hundred twenty-three thousand, nine hundred twenty-one".