51491613 has 8 divisors (see below), whose sum is σ = 70330176. Its totient is φ = 33490400.

The previous prime is 51491603. The next prime is 51491621. The reversal of 51491613 is 31619415.

51491613 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 51491613 - 2⁸ = 51491357 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51491603) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 209193 + ... + 209438.

It is an arithmetic number, because the mean of its divisors is an integer number (8791272).

Almost surely, 2^51491613 is an apocalyptic number.

It is an amenable number.

51491613 is a deficient number, since it is larger than the sum of its proper divisors (18838563).

51491613 is a wasteful number, since it uses less digits than its factorization.

51491613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 418675.

The product of its digits is 3240, while the sum is 30.

The square root of 51491613 is about 7175.7656734317. The cubic root of 51491613 is about 372.0307452332.

The spelling of 51491613 in words is "fifty-one million, four hundred ninety-one thousand, six hundred thirteen".