81533069 has 4 divisors (see below), whose sum is σ = 84163200. Its totient is φ = 78902940.

The previous prime is 81533041. The next prime is 81533077. The reversal of 81533069 is 96033518.

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 81533069 - 2²⁰ = 80484493 is a prime.

It is a super-2 number, since 2×81533069² = 13295282681117522, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81533029) 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, 1315019 + ... + 1315080.

It is an arithmetic number, because the mean of its divisors is an integer number (21040800).

Almost surely, 2^81533069 is an apocalyptic number.

It is an amenable number.

81533069 is a deficient number, since it is larger than the sum of its proper divisors (2630131).

81533069 is a wasteful number, since it uses less digits than its factorization.

81533069 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2630130.

The product of its (nonzero) digits is 19440, while the sum is 35.

The square root of 81533069 is about 9029.5663794005. The cubic root of 81533069 is about 433.6219551894.

The spelling of 81533069 in words is "eighty-one million, five hundred thirty-three thousand, sixty-nine".