81397743 has 16 divisors (see below), whose sum is σ = 127388160. Its totient is φ = 45255456.

The previous prime is 81397739. The next prime is 81397769. The reversal of 81397743 is 34779318.

It is not a de Polignac number, because 81397743 - 2² = 81397739 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81397695 and 81397704.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81397733) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 51603 + ... + 53156.

It is an arithmetic number, because the mean of its divisors is an integer number (7961760).

Almost surely, 2^81397743 is an apocalyptic number.

81397743 is a deficient number, since it is larger than the sum of its proper divisors (45990417).

81397743 is a wasteful number, since it uses less digits than its factorization.

81397743 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104806.

The product of its digits is 127008, while the sum is 42.

The square root of 81397743 is about 9022.0697736163. The cubic root of 81397743 is about 433.3819183526.

The spelling of 81397743 in words is "eighty-one million, three hundred ninety-seven thousand, seven hundred forty-three".