81623239 has 8 divisors (see below), whose sum is σ = 86527008. Its totient is φ = 76730880.

The previous prime is 81623203. The next prime is 81623249. The reversal of 81623239 is 93232618.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81623239 - 2⁷ = 81623111 is a prime.

It is a super-2 number, since 2×81623239² = 13324706289702242, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81623249) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15199 + ... + 19855.

It is an arithmetic number, because the mean of its divisors is an integer number (10815876).

Almost surely, 2^81623239 is an apocalyptic number.

81623239 is a deficient number, since it is larger than the sum of its proper divisors (4903769).

81623239 is a wasteful number, since it uses less digits than its factorization.

81623239 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5705.

The product of its digits is 15552, while the sum is 34.

The square root of 81623239 is about 9034.5580412104. The cubic root of 81623239 is about 433.7817483758.

The spelling of 81623239 in words is "eighty-one million, six hundred twenty-three thousand, two hundred thirty-nine".