81264133 has 2 divisors, whose sum is σ = 81264134. Its totient is φ = 81264132.

The previous prime is 81264101. The next prime is 81264137. The reversal of 81264133 is 33146218.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 49533444 + 31730689 = 7038^2 + 5633^2 .

It is a cyclic number.

It is not a de Polignac number, because 81264133 - 2⁵ = 81264101 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81264137) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40632066 + 40632067.

It is an arithmetic number, because the mean of its divisors is an integer number (40632067).

Almost surely, 2^81264133 is an apocalyptic number.

It is an amenable number.

81264133 is a deficient number, since it is larger than the sum of its proper divisors (1).

81264133 is an equidigital number, since it uses as much as digits as its factorization.

81264133 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3456, while the sum is 28.

The square root of 81264133 is about 9014.6621123590. The cubic root of 81264133 is about 433.1446641525.

The spelling of 81264133 in words is "eighty-one million, two hundred sixty-four thousand, one hundred thirty-three".