278779591 has 2 divisors, whose sum is σ = 278779592. Its totient is φ = 278779590.

The previous prime is 278779547. The next prime is 278779601. The reversal of 278779591 is 195977872.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-278779591 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (278779531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 139389795 + 139389796.

It is an arithmetic number, because the mean of its divisors is an integer number (139389796).

Almost surely, 2^278779591 is an apocalyptic number.

278779591 is a deficient number, since it is larger than the sum of its proper divisors (1).

278779591 is an equidigital number, since it uses as much as digits as its factorization.

278779591 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2222640, while the sum is 55.

The square root of 278779591 is about 16696.6940140855. The cubic root of 278779591 is about 653.2613923343.

The spelling of 278779591 in words is "two hundred seventy-eight million, seven hundred seventy-nine thousand, five hundred ninety-one".