51491249 has 8 divisors (see below), whose sum is σ = 55549800. Its totient is φ = 47547136.

The previous prime is 51491213. The next prime is 51491263. The reversal of 51491249 is 94219415.

It can be written as a sum of positive squares in 4 ways, for example, as 5793649 + 45697600 = 2407^2 + 6760^2 .

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 51491249 - 2⁸ = 51490993 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51491149) 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, 27674 + ... + 29475.

It is an arithmetic number, because the mean of its divisors is an integer number (6943725).

Almost surely, 2^51491249 is an apocalyptic number.

It is an amenable number.

51491249 is a deficient number, since it is larger than the sum of its proper divisors (4058551).

51491249 is a wasteful number, since it uses less digits than its factorization.

51491249 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57219.

The product of its digits is 12960, while the sum is 35.

The square root of 51491249 is about 7175.7403102398. The cubic root of 51491249 is about 372.0298685887.

The spelling of 51491249 in words is "fifty-one million, four hundred ninety-one thousand, two hundred forty-nine".