51207391 has 2 divisors, whose sum is σ = 51207392. Its totient is φ = 51207390.

The previous prime is 51207389. The next prime is 51207421. The reversal of 51207391 is 19370215.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 51207391 - 2¹ = 51207389 is a prime.

Together with 51207389, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51207991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25603695 + 25603696.

It is an arithmetic number, because the mean of its divisors is an integer number (25603696).

Almost surely, 2^51207391 is an apocalyptic number.

51207391 is a deficient number, since it is larger than the sum of its proper divisors (1).

51207391 is an equidigital number, since it uses as much as digits as its factorization.

51207391 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1890, while the sum is 28.

The square root of 51207391 is about 7155.9339711878. The cubic root of 51207391 is about 371.3449735288.

The spelling of 51207391 in words is "fifty-one million, two hundred seven thousand, three hundred ninety-one".