90161690 has 16 divisors (see below), whose sum is σ = 163899720. Its totient is φ = 35707200.

The previous prime is 90161681. The next prime is 90161723. The reversal of 90161690 is 9616109.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 84290761 + 5870929 = 9181^2 + 2423^2 .

It is a super-2 number, since 2×90161690² = 16258260687312200, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 43625 + ... + 45644.

Almost surely, 2^90161690 is an apocalyptic number.

90161690 is a deficient number, since it is larger than the sum of its proper divisors (73738030).

90161690 is a wasteful number, since it uses less digits than its factorization.

90161690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89377.

The product of its (nonzero) digits is 2916, while the sum is 32.

The square root of 90161690 is about 9495.3509677105. The cubic root of 90161690 is about 448.4086838553.

Adding to 90161690 its reverse (9616109), we get a palindrome (99777799).

The spelling of 90161690 in words is "ninety million, one hundred sixty-one thousand, six hundred ninety".