81524071 has 4 divisors (see below), whose sum is σ = 81542200. Its totient is φ = 81505944.

The previous prime is 81524063. The next prime is 81524083. The reversal of 81524071 is 17042518.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 17042518 = 2 ⋅8521259.

It is a cyclic number.

It is not a de Polignac number, because 81524071 - 2³ = 81524063 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81524021) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3340 + ... + 13198.

It is an arithmetic number, because the mean of its divisors is an integer number (20385550).

Almost surely, 2^81524071 is an apocalyptic number.

81524071 is a deficient number, since it is larger than the sum of its proper divisors (18129).

81524071 is an equidigital number, since it uses as much as digits as its factorization.

81524071 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18128.

The product of its (nonzero) digits is 2240, while the sum is 28.

The square root of 81524071 is about 9029.0681135984. The cubic root of 81524071 is about 433.6060030776.

Adding to 81524071 its reverse (17042518), we get a palindrome (98566589).

The spelling of 81524071 in words is "eighty-one million, five hundred twenty-four thousand, seventy-one".