51981311 has 8 divisors (see below), whose sum is σ = 56112480. Its totient is φ = 48006112.

The previous prime is 51981277. The next prime is 51981313. The reversal of 51981311 is 11318915.

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 51981311 - 2⁶ = 51981247 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51981313) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38300 + ... + 39633.

It is an arithmetic number, because the mean of its divisors is an integer number (7014060).

Almost surely, 2^51981311 is an apocalyptic number.

51981311 is a deficient number, since it is larger than the sum of its proper divisors (4131169).

51981311 is a wasteful number, since it uses less digits than its factorization.

51981311 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77985.

The product of its digits is 1080, while the sum is 29.

The square root of 51981311 is about 7209.8065854779. The cubic root of 51981311 is about 373.2063943614.

The spelling of 51981311 in words is "fifty-one million, nine hundred eighty-one thousand, three hundred eleven".