279731989 has 2 divisors, whose sum is σ = 279731990. Its totient is φ = 279731988.

The previous prime is 279731929. The next prime is 279732043. The reversal of 279731989 is 989137972.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 158004900 + 121727089 = 12570^2 + 11033^2 .

It is a cyclic number.

It is not a de Polignac number, because 279731989 - 2⁷ = 279731861 is a prime.

It is a super-2 number, since 2×279731989² = 156499971339792242, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (279731929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 139865994 + 139865995.

It is an arithmetic number, because the mean of its divisors is an integer number (139865995).

Almost surely, 2^279731989 is an apocalyptic number.

It is an amenable number.

279731989 is a deficient number, since it is larger than the sum of its proper divisors (1).

279731989 is an equidigital number, since it uses as much as digits as its factorization.

279731989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1714608, while the sum is 55.

The square root of 279731989 is about 16725.1902530285. The cubic root of 279731989 is about 654.0044616529.

The spelling of 279731989 in words is "two hundred seventy-nine million, seven hundred thirty-one thousand, nine hundred eighty-nine".