51309778 has 32 divisors (see below), whose sum is σ = 85800960. Its totient is φ = 22861440.

The previous prime is 51309773. The next prime is 51309781. The reversal of 51309778 is 87790315.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 51309778.

It is not an unprimeable number, because it can be changed into a prime (51309773) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 135193 + ... + 135571.

It is an arithmetic number, because the mean of its divisors is an integer number (2681280).

Almost surely, 2^51309778 is an apocalyptic number.

51309778 is a deficient number, since it is larger than the sum of its proper divisors (34491182).

51309778 is a wasteful number, since it uses less digits than its factorization.

51309778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 562.

The product of its (nonzero) digits is 52920, while the sum is 40.

The square root of 51309778 is about 7163.0843915174. The cubic root of 51309778 is about 371.5923049185.

The spelling of 51309778 in words is "fifty-one million, three hundred nine thousand, seven hundred seventy-eight".