51215813 has 8 divisors (see below), whose sum is σ = 57674496. Its totient is φ = 45057600.

The previous prime is 51215809. The next prime is 51215839. The reversal of 51215813 is 31851215.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 51215813 - 2² = 51215809 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51215803) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 74756 + ... + 75437.

It is an arithmetic number, because the mean of its divisors is an integer number (7209312).

Almost surely, 2^51215813 is an apocalyptic number.

It is an amenable number.

51215813 is a deficient number, since it is larger than the sum of its proper divisors (6458683).

51215813 is a wasteful number, since it uses less digits than its factorization.

51215813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 150235.

The product of its digits is 1200, while the sum is 26.

The square root of 51215813 is about 7156.5224096624. The cubic root of 51215813 is about 371.3653305897.

The spelling of 51215813 in words is "fifty-one million, two hundred fifteen thousand, eight hundred thirteen".