90817281 has 40 divisors (see below), whose sum is σ = 145290024. Its totient is φ = 56332800.

The previous prime is 90817273. The next prime is 90817297. The reversal of 90817281 is 18271809.

It can be written as a sum of positive squares in 4 ways, for example, as 37015056 + 53802225 = 6084^2 + 7335^2 .

It is not a de Polignac number, because 90817281 - 2³ = 90817273 is a prime.

It is a super-2 number, since 2×90817281² = 16495557056465922, which contains 22 as substring.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (90817201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 138751 + ... + 139403.

Almost surely, 2^90817281 is an apocalyptic number.

It is an amenable number.

90817281 is a deficient number, since it is larger than the sum of its proper divisors (54472743).

90817281 is a wasteful number, since it uses less digits than its factorization.

90817281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 783 (or 774 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 36.

The square root of 90817281 is about 9529.8101240266. The cubic root of 90817281 is about 449.4928954257.

The spelling of 90817281 in words is "ninety million, eight hundred seventeen thousand, two hundred eighty-one".