81533747 has 2 divisors, whose sum is σ = 81533748. Its totient is φ = 81533746.

The previous prime is 81533743. The next prime is 81533791. The reversal of 81533747 is 74733518.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81533747 - 2² = 81533743 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81533747.

It is not a weakly prime, because it can be changed into another prime (81533743) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40766873 + 40766874.

It is an arithmetic number, because the mean of its divisors is an integer number (40766874).

Almost surely, 2^81533747 is an apocalyptic number.

81533747 is a deficient number, since it is larger than the sum of its proper divisors (1).

81533747 is an equidigital number, since it uses as much as digits as its factorization.

81533747 is an evil number, because the sum of its binary digits is even.

The product of its digits is 70560, while the sum is 38.

The square root of 81533747 is about 9029.6039226535. The cubic root of 81533747 is about 433.6231571347.

The spelling of 81533747 in words is "eighty-one million, five hundred thirty-three thousand, seven hundred forty-seven".