81389023 has 2 divisors, whose sum is σ = 81389024. Its totient is φ = 81389022.

The previous prime is 81389017. The next prime is 81389069. The reversal of 81389023 is 32098318.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81389023 - 2⁹ = 81388511 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81389023.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81389083) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40694511 + 40694512.

It is an arithmetic number, because the mean of its divisors is an integer number (40694512).

Almost surely, 2^81389023 is an apocalyptic number.

81389023 is a deficient number, since it is larger than the sum of its proper divisors (1).

81389023 is an equidigital number, since it uses as much as digits as its factorization.

81389023 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10368, while the sum is 34.

The square root of 81389023 is about 9021.5865012757. The cubic root of 81389023 is about 433.3664419805.

It can be divided in two parts, 8138 and 9023, that added together give a square (17161 = 131²).

The spelling of 81389023 in words is "eighty-one million, three hundred eighty-nine thousand, twenty-three".