81199751 has 2 divisors, whose sum is σ = 81199752. Its totient is φ = 81199750.

The previous prime is 81199747. The next prime is 81199771. The reversal of 81199751 is 15799118.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81199751 - 2² = 81199747 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81199699 and 81199708.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81199771) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40599875 + 40599876.

It is an arithmetic number, because the mean of its divisors is an integer number (40599876).

Almost surely, 2^81199751 is an apocalyptic number.

81199751 is a deficient number, since it is larger than the sum of its proper divisors (1).

81199751 is an equidigital number, since it uses as much as digits as its factorization.

81199751 is an evil number, because the sum of its binary digits is even.

The product of its digits is 22680, while the sum is 41.

The square root of 81199751 is about 9011.0904445578. The cubic root of 81199751 is about 433.0302467728.

The spelling of 81199751 in words is "eighty-one million, one hundred ninety-nine thousand, seven hundred fifty-one".