90173921 has 8 divisors (see below), whose sum is σ = 94131624. Its totient is φ = 86296320.

The previous prime is 90173917. The next prime is 90173927. The reversal of 90173921 is 12937109.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 16900321 + 73273600 = 4111^2 + 8560^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 90173921 - 2² = 90173917 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (90173927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17720 + ... + 22233.

It is an arithmetic number, because the mean of its divisors is an integer number (11766453).

Almost surely, 2^90173921 is an apocalyptic number.

It is an amenable number.

90173921 is a deficient number, since it is larger than the sum of its proper divisors (3957703).

90173921 is a wasteful number, since it uses less digits than its factorization.

90173921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40051.

The product of its (nonzero) digits is 3402, while the sum is 32.

The square root of 90173921 is about 9495.9949978925. The cubic root of 90173921 is about 448.4289594241.

The spelling of 90173921 in words is "ninety million, one hundred seventy-three thousand, nine hundred twenty-one".