81726731 has 2 divisors, whose sum is σ = 81726732. Its totient is φ = 81726730.

The previous prime is 81726691. The next prime is 81726737. The reversal of 81726731 is 13762718.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81726731 - 2¹⁸ = 81464587 is a prime.

It is a super-2 number, since 2×81726731² = 13358517119892722, which contains 22 as substring.

It is a Sophie Germain prime.

It is a junction number, because it is equal to n+sod(n) for n = 81726691 and 81726700.

It is not a weakly prime, because it can be changed into another prime (81726737) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40863365 + 40863366.

It is an arithmetic number, because the mean of its divisors is an integer number (40863366).

Almost surely, 2^81726731 is an apocalyptic number.

81726731 is a deficient number, since it is larger than the sum of its proper divisors (1).

81726731 is an equidigital number, since it uses as much as digits as its factorization.

81726731 is an evil number, because the sum of its binary digits is even.

The product of its digits is 14112, while the sum is 35.

The square root of 81726731 is about 9040.2837897933. The cubic root of 81726731 is about 433.9650049296.

The spelling of 81726731 in words is "eighty-one million, seven hundred twenty-six thousand, seven hundred thirty-one".