51087391 has 2 divisors, whose sum is σ = 51087392. Its totient is φ = 51087390.

The previous prime is 51087383. The next prime is 51087427. The reversal of 51087391 is 19378015.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 51087391 - 2³ = 51087383 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51087331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25543695 + 25543696.

It is an arithmetic number, because the mean of its divisors is an integer number (25543696).

Almost surely, 2^51087391 is an apocalyptic number.

51087391 is a deficient number, since it is larger than the sum of its proper divisors (1).

51087391 is an equidigital number, since it uses as much as digits as its factorization.

51087391 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7560, while the sum is 34.

The square root of 51087391 is about 7147.5444034997. The cubic root of 51087391 is about 371.0546752606.

The spelling of 51087391 in words is "fifty-one million, eighty-seven thousand, three hundred ninety-one".