81961727 has 2 divisors, whose sum is σ = 81961728. Its totient is φ = 81961726.

The previous prime is 81961723. The next prime is 81961783. The reversal of 81961727 is 72716918.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81961727 - 2² = 81961723 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81961723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40980863 + 40980864.

It is an arithmetic number, because the mean of its divisors is an integer number (40980864).

Almost surely, 2^81961727 is an apocalyptic number.

81961727 is a deficient number, since it is larger than the sum of its proper divisors (1).

81961727 is an equidigital number, since it uses as much as digits as its factorization.

81961727 is an evil number, because the sum of its binary digits is even.

The product of its digits is 42336, while the sum is 41.

The square root of 81961727 is about 9053.2716185918. The cubic root of 81961727 is about 434.3805460500.

The spelling of 81961727 in words is "eighty-one million, nine hundred sixty-one thousand, seven hundred twenty-seven".