51907981 has 8 divisors (see below), whose sum is σ = 56403200. Its totient is φ = 47589120.

The previous prime is 51907979. The next prime is 51907991. The reversal of 51907981 is 18970915.

It is a happy number.

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 51907981 - 2¹ = 51907979 is a prime.

It is a super-2 number, since 2×51907981² = 5388876982992722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51907931) 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, 43476 + ... + 44653.

It is an arithmetic number, because the mean of its divisors is an integer number (7050400).

Almost surely, 2^51907981 is an apocalyptic number.

It is an amenable number.

51907981 is a deficient number, since it is larger than the sum of its proper divisors (4495219).

51907981 is a wasteful number, since it uses less digits than its factorization.

51907981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 88179.

The product of its (nonzero) digits is 22680, while the sum is 40.

The square root of 51907981 is about 7204.7193560888. The cubic root of 51907981 is about 373.0308177716.

The spelling of 51907981 in words is "fifty-one million, nine hundred seven thousand, nine hundred eighty-one".