90221731 has 4 divisors (see below), whose sum is σ = 91568392. Its totient is φ = 88875072.

The previous prime is 90221723. The next prime is 90221743. The reversal of 90221731 is 13712209.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 90221731 - 2³ = 90221723 is a prime.

It is a super-2 number, since 2×90221731² = 16279921489272722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 90221696 and 90221705.

It is not an unprimeable number, because it can be changed into a prime (90221231) 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, 673230 + ... + 673363.

It is an arithmetic number, because the mean of its divisors is an integer number (22892098).

Almost surely, 2^90221731 is an apocalyptic number.

90221731 is a deficient number, since it is larger than the sum of its proper divisors (1346661).

90221731 is a wasteful number, since it uses less digits than its factorization.

90221731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1346660.

The product of its (nonzero) digits is 756, while the sum is 25.

The square root of 90221731 is about 9498.5120413673. The cubic root of 90221731 is about 448.5081974136.

The spelling of 90221731 in words is "ninety million, two hundred twenty-one thousand, seven hundred thirty-one".