51861178778 has 8 divisors (see below), whose sum is σ = 77831687700. Its totient is φ = 25917282880.

The previous prime is 51861178769. The next prime is 51861178807. The reversal of 51861178778 is 87787116815.

It can be written as a sum of positive squares in 2 ways, for example, as 51050239249 + 810939529 = 225943^2 + 28477^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6648383 + ... + 6656178.

Almost surely, 2^51861178778 is an apocalyptic number.

51861178778 is a deficient number, since it is larger than the sum of its proper divisors (25970508922).

51861178778 is a wasteful number, since it uses less digits than its factorization.

51861178778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13306512.

The product of its digits is 5268480, while the sum is 59.

The spelling of 51861178778 in words is "fifty-one billion, eight hundred sixty-one million, one hundred seventy-eight thousand, seven hundred seventy-eight".