89809981 has 4 divisors (see below), whose sum is σ = 89906364. Its totient is φ = 89713600.

The previous prime is 89809969. The next prime is 89809987. The reversal of 89809981 is 18990898.

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

It can be written as a sum of positive squares in 2 ways, for example, as 68326756 + 21483225 = 8266^2 + 4635^2 .

It is a cyclic number.

It is not a de Polignac number, because 89809981 - 2¹⁵ = 89777213 is a prime.

It is a super-2 number, since 2×89809981² = 16131665374440722, 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 (89809987) 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, 46780 + ... + 48661.

It is an arithmetic number, because the mean of its divisors is an integer number (22476591).

Almost surely, 2^89809981 is an apocalyptic number.

It is an amenable number.

89809981 is a deficient number, since it is larger than the sum of its proper divisors (96383).

89809981 is an equidigital number, since it uses as much as digits as its factorization.

89809981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96382.

The product of its (nonzero) digits is 373248, while the sum is 52.

The square root of 89809981 is about 9476.8128081122. The cubic root of 89809981 is about 447.8248627843.

The spelling of 89809981 in words is "eighty-nine million, eight hundred nine thousand, nine hundred eighty-one".