81375851 has 2 divisors, whose sum is σ = 81375852. Its totient is φ = 81375850.

The previous prime is 81375793. The next prime is 81375883. The reversal of 81375851 is 15857318.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81375851 - 2¹⁸ = 81113707 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81375751) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40687925 + 40687926.

It is an arithmetic number, because the mean of its divisors is an integer number (40687926).

Almost surely, 2^81375851 is an apocalyptic number.

81375851 is a deficient number, since it is larger than the sum of its proper divisors (1).

81375851 is an equidigital number, since it uses as much as digits as its factorization.

81375851 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 33600, while the sum is 38.

The square root of 81375851 is about 9020.8564449281. The cubic root of 81375851 is about 433.3430620433.

The spelling of 81375851 in words is "eighty-one million, three hundred seventy-five thousand, eight hundred fifty-one".