87899981 has 4 divisors (see below), whose sum is σ = 94661532. Its totient is φ = 81138432.

The previous prime is 87899971. The next prime is 87899993. The reversal of 87899981 is 18999878.

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 17926756 + 69973225 = 4234^2 + 8365^2 .

It is a cyclic number.

It is not a de Polignac number, because 87899981 - 2¹⁴ = 87883597 is a prime.

It is a super-2 number, since 2×87899981² = 15452813319600722, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 87899981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (87899921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3380756 + ... + 3380781.

It is an arithmetic number, because the mean of its divisors is an integer number (23665383).

Almost surely, 2^87899981 is an apocalyptic number.

It is an amenable number.

87899981 is a deficient number, since it is larger than the sum of its proper divisors (6761551).

87899981 is a wasteful number, since it uses less digits than its factorization.

87899981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6761550.

The product of its digits is 2612736, while the sum is 59.

The square root of 87899981 is about 9375.4989733880. The cubic root of 87899981 is about 444.6274388778.

The spelling of 87899981 in words is "eighty-seven million, eight hundred ninety-nine thousand, nine hundred eighty-one".