81382569 has 4 divisors (see below), whose sum is σ = 108510096. Its totient is φ = 54255044.

The previous prime is 81382559. The next prime is 81382577. The reversal of 81382569 is 96528318.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81382569 - 2⁸ = 81382313 is a prime.

It is a super-2 number, since 2×81382569² = 13246245074079522, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81382569.

It is not an unprimeable number, because it can be changed into a prime (81382559) 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, 13563759 + ... + 13563764.

It is an arithmetic number, because the mean of its divisors is an integer number (27127524).

Almost surely, 2^81382569 is an apocalyptic number.

It is an amenable number.

81382569 is a deficient number, since it is larger than the sum of its proper divisors (27127527).

81382569 is a wasteful number, since it uses less digits than its factorization.

81382569 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27127526.

The product of its digits is 103680, while the sum is 42.

The square root of 81382569 is about 9021.2287965665. The cubic root of 81382569 is about 433.3549866234.

The spelling of 81382569 in words is "eighty-one million, three hundred eighty-two thousand, five hundred sixty-nine".