51072813 has 12 divisors (see below), whose sum is σ = 80478528. Its totient is φ = 30953160.

The previous prime is 51072809. The next prime is 51072823. The reversal of 51072813 is 31827015.

51072813 is a `hidden beast` number, since 510 + 72 + 81 + 3 = 666.

It is not a de Polignac number, because 51072813 - 2² = 51072809 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51072803) 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, 257845 + ... + 258042.

It is an arithmetic number, because the mean of its divisors is an integer number (6706544).

Almost surely, 2^51072813 is an apocalyptic number.

It is an amenable number.

51072813 is a deficient number, since it is larger than the sum of its proper divisors (29405715).

51072813 is a wasteful number, since it uses less digits than its factorization.

51072813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 515904 (or 515901 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 27.

The square root of 51072813 is about 7146.5245399425. The cubic root of 51072813 is about 371.0193779035.

Adding to 51072813 its reverse (31827015), we get a palindrome (82899828).

The spelling of 51072813 in words is "fifty-one million, seventy-two thousand, eight hundred thirteen".