81747019 has 2 divisors, whose sum is σ = 81747020. Its totient is φ = 81747018.

The previous prime is 81746981. The next prime is 81747049. The reversal of 81747019 is 91074718.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81747019 - 2⁷ = 81746891 is a prime.

It is a super-2 number, since 2×81747019² = 13365150230772722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81747049) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40873509 + 40873510.

It is an arithmetic number, because the mean of its divisors is an integer number (40873510).

Almost surely, 2^81747019 is an apocalyptic number.

81747019 is a deficient number, since it is larger than the sum of its proper divisors (1).

81747019 is an equidigital number, since it uses as much as digits as its factorization.

81747019 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 14112, while the sum is 37.

The square root of 81747019 is about 9041.4058088330. The cubic root of 81747019 is about 434.0009113928. Note that the first 3 decimals are identical.

The spelling of 81747019 in words is "eighty-one million, seven hundred forty-seven thousand, nineteen".