659998891 has 2 divisors, whose sum is σ = 659998892. Its totient is φ = 659998890.

The previous prime is 659998879. The next prime is 659998903. The reversal of 659998891 is 198899956.

It is a balanced prime because it is at equal distance from previous prime (659998879) and next prime (659998903).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-659998891 is a prime.

It is a super-2 number, since 2×659998891² = 871197072242459762, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (659998811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 329999445 + 329999446.

It is an arithmetic number, because the mean of its divisors is an integer number (329999446).

Almost surely, 2^659998891 is an apocalyptic number.

659998891 is a deficient number, since it is larger than the sum of its proper divisors (1).

659998891 is an equidigital number, since it uses as much as digits as its factorization.

659998891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12597120, while the sum is 64.

The square root of 659998891 is about 25690.4435734380. The cubic root of 659998891 is about 870.6582814602.

The spelling of 659998891 in words is "six hundred fifty-nine million, nine hundred ninety-eight thousand, eight hundred ninety-one".