81542297 has 2 divisors, whose sum is σ = 81542298. Its totient is φ = 81542296.

The previous prime is 81542273. The next prime is 81542323. The reversal of 81542297 is 79224518.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 78783376 + 2758921 = 8876^2 + 1661^2 .

It is a cyclic number.

It is not a de Polignac number, because 81542297 - 2¹⁶ = 81476761 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81542297.

It is not a weakly prime, because it can be changed into another prime (81542207) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40771148 + 40771149.

It is an arithmetic number, because the mean of its divisors is an integer number (40771149).

Almost surely, 2^81542297 is an apocalyptic number.

It is an amenable number.

81542297 is a deficient number, since it is larger than the sum of its proper divisors (1).

81542297 is an equidigital number, since it uses as much as digits as its factorization.

81542297 is an evil number, because the sum of its binary digits is even.

The product of its digits is 40320, while the sum is 38.

The square root of 81542297 is about 9030.0773529356. The cubic root of 81542297 is about 433.6383138379.

The spelling of 81542297 in words is "eighty-one million, five hundred forty-two thousand, two hundred ninety-seven".