51709491 has 12 divisors (see below), whose sum is σ = 75378160. Its totient is φ = 34156080.

The previous prime is 51709481. The next prime is 51709501. The reversal of 51709491 is 19490715.

It is an interprime number because it is at equal distance from previous prime (51709481) and next prime (51709501).

It is not a de Polignac number, because 51709491 - 2¹⁰ = 51708467 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51709421) 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 11 ways as a sum of consecutive naturals, for example, 25375 + ... + 27336.

Almost surely, 2^51709491 is an apocalyptic number.

51709491 is a deficient number, since it is larger than the sum of its proper divisors (23668669).

51709491 is a wasteful number, since it uses less digits than its factorization.

51709491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52826 (or 52823 counting only the distinct ones).

The product of its (nonzero) digits is 11340, while the sum is 36.

The square root of 51709491 is about 7190.9311636255. The cubic root of 51709491 is about 372.5547351366.

The spelling of 51709491 in words is "fifty-one million, seven hundred nine thousand, four hundred ninety-one".