90898781 has 4 divisors (see below), whose sum is σ = 90929532. Its totient is φ = 90868032.

The previous prime is 90898777. The next prime is 90898807. The reversal of 90898781 is 18789809.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18789809 = 179 ⋅104971.

It can be written as a sum of positive squares in 2 ways, for example, as 68724100 + 22174681 = 8290^2 + 4709^2 .

It is a cyclic number.

It is not a de Polignac number, because 90898781 - 2² = 90898777 is a prime.

It is a super-2 number, since 2×90898781² = 16525176774571922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (90898721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10406 + ... + 17031.

It is an arithmetic number, because the mean of its divisors is an integer number (22732383).

Almost surely, 2^90898781 is an apocalyptic number.

It is an amenable number.

90898781 is a deficient number, since it is larger than the sum of its proper divisors (30751).

90898781 is a wasteful number, since it uses less digits than its factorization.

90898781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30750.

The product of its (nonzero) digits is 290304, while the sum is 50.

The square root of 90898781 is about 9534.0852209323. The cubic root of 90898781 is about 449.6273144760.

The spelling of 90898781 in words is "ninety million, eight hundred ninety-eight thousand, seven hundred eighty-one".