81931063 has 2 divisors, whose sum is σ = 81931064. Its totient is φ = 81931062.

The previous prime is 81931033. The next prime is 81931067. The reversal of 81931063 is 36013918.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81931063 - 2¹³ = 81922871 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81931067) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40965531 + 40965532.

It is an arithmetic number, because the mean of its divisors is an integer number (40965532).

Almost surely, 2^81931063 is an apocalyptic number.

81931063 is a deficient number, since it is larger than the sum of its proper divisors (1).

81931063 is an equidigital number, since it uses as much as digits as its factorization.

81931063 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3888, while the sum is 31.

The square root of 81931063 is about 9051.5779287371. The cubic root of 81931063 is about 434.3263682974.

The spelling of 81931063 in words is "eighty-one million, nine hundred thirty-one thousand, sixty-three".