51618820391 has 2 divisors, whose sum is σ = 51618820392. Its totient is φ = 51618820390.

The previous prime is 51618820381. The next prime is 51618820403. The reversal of 51618820391 is 19302881615.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 51618820391 - 2⁶ = 51618820327 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51618820321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25809410195 + 25809410196.

It is an arithmetic number, because the mean of its divisors is an integer number (25809410196).

Almost surely, 2^51618820391 is an apocalyptic number.

51618820391 is a deficient number, since it is larger than the sum of its proper divisors (1).

51618820391 is an equidigital number, since it uses as much as digits as its factorization.

51618820391 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 103680, while the sum is 44.

The spelling of 51618820391 in words is "fifty-one billion, six hundred eighteen million, eight hundred twenty thousand, three hundred ninety-one".