51431389 has 2 divisors, whose sum is σ = 51431390. Its totient is φ = 51431388.

The previous prime is 51431383. The next prime is 51431399. The reversal of 51431389 is 98313415.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 40322500 + 11108889 = 6350^2 + 3333^2 .

It is a cyclic number.

It is not a de Polignac number, because 51431389 - 2⁹ = 51430877 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51431383) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25715694 + 25715695.

It is an arithmetic number, because the mean of its divisors is an integer number (25715695).

Almost surely, 2^51431389 is an apocalyptic number.

It is an amenable number.

51431389 is a deficient number, since it is larger than the sum of its proper divisors (1).

51431389 is an equidigital number, since it uses as much as digits as its factorization.

51431389 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12960, while the sum is 34.

The square root of 51431389 is about 7171.5680990980. The cubic root of 51431389 is about 371.8856476861.

The spelling of 51431389 in words is "fifty-one million, four hundred thirty-one thousand, three hundred eighty-nine".