81612238 has 4 divisors (see below), whose sum is σ = 122418360. Its totient is φ = 40806118.

The previous prime is 81612227. The next prime is 81612241. The reversal of 81612238 is 83221618.

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

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20403058 + ... + 20403061.

It is an arithmetic number, because the mean of its divisors is an integer number (30604590).

Almost surely, 2^81612238 is an apocalyptic number.

81612238 is a deficient number, since it is larger than the sum of its proper divisors (40806122).

81612238 is a wasteful number, since it uses less digits than its factorization.

81612238 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40806121.

The product of its digits is 4608, while the sum is 31.

The square root of 81612238 is about 9033.9491917987. The cubic root of 81612238 is about 433.7622594514.

The spelling of 81612238 in words is "eighty-one million, six hundred twelve thousand, two hundred thirty-eight".