51939917 has 4 divisors (see below), whose sum is σ = 52416540. Its totient is φ = 51463296.

The previous prime is 51939869. The next prime is 51939929. The reversal of 51939917 is 71993915.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 13920361 + 38019556 = 3731^2 + 6166^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51939917 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 (51938917) 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, 238148 + ... + 238365.

It is an arithmetic number, because the mean of its divisors is an integer number (13104135).

Almost surely, 2^51939917 is an apocalyptic number.

It is an amenable number.

51939917 is a deficient number, since it is larger than the sum of its proper divisors (476623).

51939917 is a wasteful number, since it uses less digits than its factorization.

51939917 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 476622.

The product of its digits is 76545, while the sum is 44.

The square root of 51939917 is about 7206.9353403510. The cubic root of 51939917 is about 373.1073035685.

The spelling of 51939917 in words is "fifty-one million, nine hundred thirty-nine thousand, nine hundred seventeen".