81641927 has 4 divisors (see below), whose sum is σ = 85191600. Its totient is φ = 78092256.

The previous prime is 81641909. The next prime is 81641929. The reversal of 81641927 is 72914618.

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 81641927 - 2⁸ = 81641671 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 (81641929) 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, 1774802 + ... + 1774847.

It is an arithmetic number, because the mean of its divisors is an integer number (21297900).

Almost surely, 2^81641927 is an apocalyptic number.

81641927 is a deficient number, since it is larger than the sum of its proper divisors (3549673).

81641927 is a wasteful number, since it uses less digits than its factorization.

81641927 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3549672.

The product of its digits is 24192, while the sum is 38.

The square root of 81641927 is about 9035.5922329419. The cubic root of 81641927 is about 433.8148512634.

The spelling of 81641927 in words is "eighty-one million, six hundred forty-one thousand, nine hundred twenty-seven".