90173721 has 8 divisors (see below), whose sum is σ = 131161824. Its totient is φ = 54650720.

The previous prime is 90173711. The next prime is 90173737. The reversal of 90173721 is 12737109.

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 90173721 - 2⁵ = 90173689 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (90173711) 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, 1366236 + ... + 1366301.

It is an arithmetic number, because the mean of its divisors is an integer number (16395228).

Almost surely, 2^90173721 is an apocalyptic number.

It is an amenable number.

90173721 is a deficient number, since it is larger than the sum of its proper divisors (40988103).

90173721 is a wasteful number, since it uses less digits than its factorization.

90173721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2732551.

The product of its (nonzero) digits is 2646, while the sum is 30.

The square root of 90173721 is about 9495.9844671314. The cubic root of 90173721 is about 448.4286278949.

The spelling of 90173721 in words is "ninety million, one hundred seventy-three thousand, seven hundred twenty-one".