2578123557 has 12 divisors (see below), whose sum is σ = 3725892300. Its totient is φ = 1717855488.

The previous prime is 2578123517. The next prime is 2578123621. The reversal of 2578123557 is 7553218752.

2578123557 is a `hidden beast` number, since 2 + 5 + 78 + 1 + 23 + 557 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 1978559361 + 599564196 = 44481^2 + 24486^2 .

It is not a de Polignac number, because 2578123557 - 2¹² = 2578119461 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2578123517) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 55948 + ... + 91029.

It is an arithmetic number, because the mean of its divisors is an integer number (310491025).

Almost surely, 2^2578123557 is an apocalyptic number.

It is an amenable number.

2578123557 is a deficient number, since it is larger than the sum of its proper divisors (1147768743).

2578123557 is a wasteful number, since it uses less digits than its factorization.

2578123557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 148932 (or 148929 counting only the distinct ones).

The product of its digits is 588000, while the sum is 45.

The square root of 2578123557 is about 50775.2258192910. The cubic root of 2578123557 is about 1371.2013822834.

The spelling of 2578123557 in words is "two billion, five hundred seventy-eight million, one hundred twenty-three thousand, five hundred fifty-seven".