81750133 has 2 divisors, whose sum is σ = 81750134. Its totient is φ = 81750132.

The previous prime is 81750091. The next prime is 81750167. The reversal of 81750133 is 33105718.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 66210769 + 15539364 = 8137^2 + 3942^2 .

It is a cyclic number.

It is not a de Polignac number, because 81750133 - 2¹³ = 81741941 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81750233) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40875066 + 40875067.

It is an arithmetic number, because the mean of its divisors is an integer number (40875067).

Almost surely, 2^81750133 is an apocalyptic number.

It is an amenable number.

81750133 is a deficient number, since it is larger than the sum of its proper divisors (1).

81750133 is an equidigital number, since it uses as much as digits as its factorization.

81750133 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 81750133 is about 9041.5780149264. The cubic root of 81750133 is about 434.0064221409.

The spelling of 81750133 in words is "eighty-one million, seven hundred fifty thousand, one hundred thirty-three".