2778558257 has 6 divisors (see below), whose sum is σ = 2782682994. Its totient is φ = 2774437760.

The previous prime is 2778558229. The next prime is 2778558259. The reversal of 2778558257 is 7528558772.

It can be written as a sum of positive squares in only one way, i.e., 2194079281 + 584478976 = 46841^2 + 24176^2 .

It is not a de Polignac number, because 2778558257 - 2¹² = 2778554161 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2778558259) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1838132 + ... + 1839642.

It is an arithmetic number, because the mean of its divisors is an integer number (463780499).

Almost surely, 2^2778558257 is an apocalyptic number.

It is an amenable number.

2778558257 is a deficient number, since it is larger than the sum of its proper divisors (4124737).

2778558257 is an frugal number, since it uses more digits than its factorization.

2778558257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4239 (or 2728 counting only the distinct ones).

The product of its digits is 10976000, while the sum is 56.

The square root of 2778558257 is about 52712.0314254725. The cubic root of 2778558257 is about 1405.8527528417.

The spelling of 2778558257 in words is "two billion, seven hundred seventy-eight million, five hundred fifty-eight thousand, two hundred fifty-seven".