81548531 has 4 divisors (see below), whose sum is σ = 81599232. Its totient is φ = 81497832.

The previous prime is 81548497. The next prime is 81548539. The reversal of 81548531 is 13584518.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81548531 - 2¹⁴ = 81532147 is a prime.

It is a super-2 number, since 2×81548531² = 13300325816515922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81548491 and 81548500.

It is not an unprimeable number, because it can be changed into a prime (81548539) 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, 22856 + ... + 26181.

It is an arithmetic number, because the mean of its divisors is an integer number (20399808).

Almost surely, 2^81548531 is an apocalyptic number.

81548531 is a deficient number, since it is larger than the sum of its proper divisors (50701).

81548531 is a wasteful number, since it uses less digits than its factorization.

81548531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50700.

The product of its digits is 19200, while the sum is 35.

The square root of 81548531 is about 9030.4225261059. The cubic root of 81548531 is about 433.6493642680.

The spelling of 81548531 in words is "eighty-one million, five hundred forty-eight thousand, five hundred thirty-one".