51491218 has 8 divisors (see below), whose sum is σ = 77289660. Its totient is φ = 25728000.

The previous prime is 51491213. The next prime is 51491263. The reversal of 51491218 is 81219415.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 39150049 + 12341169 = 6257^2 + 3513^2 .

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

It is a super-2 number, since 2×51491218² = 5302691062247048, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 51491218.

It is not an unprimeable number, because it can be changed into a prime (51491213) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4783 + ... + 11218.

Almost surely, 2^51491218 is an apocalyptic number.

51491218 is a deficient number, since it is larger than the sum of its proper divisors (25798442).

51491218 is a wasteful number, since it uses less digits than its factorization.

51491218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17612.

The product of its digits is 2880, while the sum is 31.

The square root of 51491218 is about 7175.7381501836. The cubic root of 51491218 is about 372.0297939293.

The spelling of 51491218 in words is "fifty-one million, four hundred ninety-one thousand, two hundred eighteen".