51431399 has 2 divisors, whose sum is σ = 51431400. Its totient is φ = 51431398.

The previous prime is 51431389. The next prime is 51431407. The reversal of 51431399 is 99313415.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 51431399 - 2⁴ = 51431383 is a prime.

It is a plaindrome in base 15.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51431329) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25715699 + 25715700.

It is an arithmetic number, because the mean of its divisors is an integer number (25715700).

Almost surely, 2^51431399 is an apocalyptic number.

51431399 is a deficient number, since it is larger than the sum of its proper divisors (1).

51431399 is an equidigital number, since it uses as much as digits as its factorization.

51431399 is an evil number, because the sum of its binary digits is even.

The product of its digits is 14580, while the sum is 35.

The square root of 51431399 is about 7171.5687962955. The cubic root of 51431399 is about 371.8856717885.

It can be divided in two parts, 514 and 31399, that added together give a palindrome (31913).

The spelling of 51431399 in words is "fifty-one million, four hundred thirty-one thousand, three hundred ninety-nine".