81231673 has 2 divisors, whose sum is σ = 81231674. Its totient is φ = 81231672.

The previous prime is 81231649. The next prime is 81231677. The reversal of 81231673 is 37613218.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 61277584 + 19954089 = 7828^2 + 4467^2 .

It is a cyclic number.

It is not a de Polignac number, because 81231673 - 2⁵ = 81231641 is a prime.

It is not a weakly prime, because it can be changed into another prime (81231677) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40615836 + 40615837.

It is an arithmetic number, because the mean of its divisors is an integer number (40615837).

Almost surely, 2^81231673 is an apocalyptic number.

It is an amenable number.

81231673 is a deficient number, since it is larger than the sum of its proper divisors (1).

81231673 is an equidigital number, since it uses as much as digits as its factorization.

81231673 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6048, while the sum is 31.

The square root of 81231673 is about 9012.8615322771. The cubic root of 81231673 is about 433.0869849620.

The spelling of 81231673 in words is "eighty-one million, two hundred thirty-one thousand, six hundred seventy-three".