87198989 has 2 divisors, whose sum is σ = 87198990. Its totient is φ = 87198988.

The previous prime is 87198977. The next prime is 87198997. The reversal of 87198989 is 98989178.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 46812964 + 40386025 = 6842^2 + 6355^2 .

It is a cyclic number.

It is not a de Polignac number, because 87198989 - 2²⁰ = 86150413 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (87198919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43599494 + 43599495.

It is an arithmetic number, because the mean of its divisors is an integer number (43599495).

Almost surely, 2^87198989 is an apocalyptic number.

It is an amenable number.

87198989 is a deficient number, since it is larger than the sum of its proper divisors (1).

87198989 is an equidigital number, since it uses as much as digits as its factorization.

87198989 is an evil number, because the sum of its binary digits is even.

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

The square root of 87198989 is about 9338.0398906837. The cubic root of 87198989 is about 443.4423324179.

The spelling of 87198989 in words is "eighty-seven million, one hundred ninety-eight thousand, nine hundred eighty-nine".