51691749 has 8 divisors (see below), whose sum is σ = 69219072. Its totient is φ = 34312800.

The previous prime is 51691721. The next prime is 51691753. The reversal of 51691749 is 94719615.

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

It is not a de Polignac number, because 51691749 - 2¹³ = 51683557 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 51691749.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51691709) 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 7 ways as a sum of consecutive naturals, for example, 36277 + ... + 37674.

It is an arithmetic number, because the mean of its divisors is an integer number (8652384).

Almost surely, 2^51691749 is an apocalyptic number.

It is an amenable number.

51691749 is a deficient number, since it is larger than the sum of its proper divisors (17527323).

51691749 is a wasteful number, since it uses less digits than its factorization.

51691749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 74187.

The product of its digits is 68040, while the sum is 42.

The square root of 51691749 is about 7189.6974206151. The cubic root of 51691749 is about 372.5121212818.

The spelling of 51691749 in words is "fifty-one million, six hundred ninety-one thousand, seven hundred forty-nine".