51899381 has 2 divisors, whose sum is σ = 51899382. Its totient is φ = 51899380.

The previous prime is 51899377. The next prime is 51899389. The reversal of 51899381 is 18399815.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 41075281 + 10824100 = 6409^2 + 3290^2 .

It is a cyclic number.

It is not a de Polignac number, because 51899381 - 2² = 51899377 is a prime.

It is a super-2 number, since 2×51899381² = 5387091496366322, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51899389) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25949690 + 25949691.

It is an arithmetic number, because the mean of its divisors is an integer number (25949691).

Almost surely, 2^51899381 is an apocalyptic number.

It is an amenable number.

51899381 is a deficient number, since it is larger than the sum of its proper divisors (1).

51899381 is an equidigital number, since it uses as much as digits as its factorization.

51899381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 77760, while the sum is 44.

The square root of 51899381 is about 7204.1225003466. The cubic root of 51899381 is about 373.0102156589.

It can be divided in two parts, 518 and 99381, that added together give a palindrome (99899).

The spelling of 51899381 in words is "fifty-one million, eight hundred ninety-nine thousand, three hundred eighty-one".