81224959 has 4 divisors (see below), whose sum is σ = 81711504. Its totient is φ = 80738416.

The previous prime is 81224921. The next prime is 81224993. The reversal of 81224959 is 95942218.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 95942218 = 2 ⋅47971109.

It is a cyclic number.

It is not a de Polignac number, because 81224959 - 2¹⁵ = 81192191 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 (81224909) 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, 243022 + ... + 243355.

It is an arithmetic number, because the mean of its divisors is an integer number (20427876).

Almost surely, 2^81224959 is an apocalyptic number.

81224959 is a deficient number, since it is larger than the sum of its proper divisors (486545).

81224959 is a wasteful number, since it uses less digits than its factorization.

81224959 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 486544.

The product of its digits is 51840, while the sum is 40.

The square root of 81224959 is about 9012.4890568588. The cubic root of 81224959 is about 433.0750527274.

The spelling of 81224959 in words is "eighty-one million, two hundred twenty-four thousand, nine hundred fifty-nine".