1989656899 has 2 divisors, whose sum is σ = 1989656900. Its totient is φ = 1989656898.

The previous prime is 1989656887. The next prime is 1989656909. The reversal of 1989656899 is 9986569891.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1989656899 - 2²³ = 1981268291 is a prime.

It is not a weakly prime, because it can be changed into another prime (1989656819) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 994828449 + 994828450.

It is an arithmetic number, because the mean of its divisors is an integer number (994828450).

Almost surely, 2^1989656899 is an apocalyptic number.

1989656899 is a deficient number, since it is larger than the sum of its proper divisors (1).

1989656899 is an equidigital number, since it uses as much as digits as its factorization.

1989656899 is an evil number, because the sum of its binary digits is even.

The product of its digits is 75582720, while the sum is 70.

The square root of 1989656899 is about 44605.5702687456. The cubic root of 1989656899 is about 1257.7453799326.

The spelling of 1989656899 in words is "one billion, nine hundred eighty-nine million, six hundred fifty-six thousand, eight hundred ninety-nine".