81447701 has 2 divisors, whose sum is σ = 81447702. Its totient is φ = 81447700.

The previous prime is 81447659. The next prime is 81447703. The reversal of 81447701 is 10774418.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 61858225 + 19589476 = 7865^2 + 4426^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81447701 is a prime.

Together with 81447703, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81447703) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40723850 + 40723851.

It is an arithmetic number, because the mean of its divisors is an integer number (40723851).

Almost surely, 2^81447701 is an apocalyptic number.

It is an amenable number.

81447701 is a deficient number, since it is larger than the sum of its proper divisors (1).

81447701 is an equidigital number, since it uses as much as digits as its factorization.

81447701 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6272, while the sum is 32.

The square root of 81447701 is about 9024.8380040863. The cubic root of 81447701 is about 433.4705631772.

The spelling of 81447701 in words is "eighty-one million, four hundred forty-seven thousand, seven hundred one".