81164438 has 4 divisors (see below), whose sum is σ = 121746660. Its totient is φ = 40582218.

The previous prime is 81164437. The next prime is 81164453. The reversal of 81164438 is 83446118.

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

It is a junction number, because it is equal to n+sod(n) for n = 81164398 and 81164407.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81164437) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20291108 + ... + 20291111.

It is an arithmetic number, because the mean of its divisors is an integer number (30436665).

Almost surely, 2^81164438 is an apocalyptic number.

81164438 is a deficient number, since it is larger than the sum of its proper divisors (40582222).

81164438 is a wasteful number, since it uses less digits than its factorization.

81164438 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40582221.

The product of its digits is 18432, while the sum is 35.

The square root of 81164438 is about 9009.1308126811. The cubic root of 81164438 is about 432.9674640911.

The spelling of 81164438 in words is "eighty-one million, one hundred sixty-four thousand, four hundred thirty-eight".