81927739 has 2 divisors, whose sum is σ = 81927740. Its totient is φ = 81927738.

The previous prime is 81927707. The next prime is 81927767. The reversal of 81927739 is 93772918.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81927739 - 2⁵ = 81927707 is a prime.

It is not a weakly prime, because it can be changed into another prime (81927239) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40963869 + 40963870.

It is an arithmetic number, because the mean of its divisors is an integer number (40963870).

Almost surely, 2^81927739 is an apocalyptic number.

81927739 is a deficient number, since it is larger than the sum of its proper divisors (1).

81927739 is an equidigital number, since it uses as much as digits as its factorization.

81927739 is an evil number, because the sum of its binary digits is even.

The product of its digits is 190512, while the sum is 46.

The square root of 81927739 is about 9051.3943124803. The cubic root of 81927739 is about 434.3204945774.

It can be divided in two parts, 8192 and 7739, that added together give a triangular number (15931 = T₁₇₈).

The spelling of 81927739 in words is "eighty-one million, nine hundred twenty-seven thousand, seven hundred thirty-nine".