51451399991 has 2 divisors, whose sum is σ = 51451399992. Its totient is φ = 51451399990.

The previous prime is 51451399973. The next prime is 51451400029. The reversal of 51451399991 is 19999315415.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 51451399991 - 2⁶ = 51451399927 is a prime.

It is a super-2 number, since 2×51451399991² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51451399921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25725699995 + 25725699996.

It is an arithmetic number, because the mean of its divisors is an integer number (25725699996).

Almost surely, 2^51451399991 is an apocalyptic number.

51451399991 is a deficient number, since it is larger than the sum of its proper divisors (1).

51451399991 is an equidigital number, since it uses as much as digits as its factorization.

51451399991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1968300, while the sum is 56.

The spelling of 51451399991 in words is "fifty-one billion, four hundred fifty-one million, three hundred ninety-nine thousand, nine hundred ninety-one".