81157529 has 2 divisors, whose sum is σ = 81157530. Its totient is φ = 81157528.

The previous prime is 81157523. The next prime is 81157543. The reversal of 81157529 is 92575118.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 79619929 + 1537600 = 8923^2 + 1240^2 .

It is a cyclic number.

It is not a de Polignac number, because 81157529 - 2¹⁶ = 81091993 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81157492 and 81157501.

It is not a weakly prime, because it can be changed into another prime (81157523) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40578764 + 40578765.

It is an arithmetic number, because the mean of its divisors is an integer number (40578765).

Almost surely, 2^81157529 is an apocalyptic number.

It is an amenable number.

81157529 is a deficient number, since it is larger than the sum of its proper divisors (1).

81157529 is an equidigital number, since it uses as much as digits as its factorization.

81157529 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 25200, while the sum is 38.

The square root of 81157529 is about 9008.7473602050. The cubic root of 81157529 is about 432.9551785090.

The spelling of 81157529 in words is "eighty-one million, one hundred fifty-seven thousand, five hundred twenty-nine".