81389050623 has 24 divisors (see below), whose sum is σ = 122120547120. Its totient is φ = 52170935040.

The previous prime is 81389050607. The next prime is 81389050643. The reversal of 81389050623 is 32605098318.

It is a happy number.

81389050623 is a `hidden beast` number, since 8 + 1 + 38 + 90 + 506 + 23 = 666.

It is not a de Polignac number, because 81389050623 - 2⁴ = 81389050607 is a prime.

It is a super-2 number, since 2×81389050623² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81389050643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 584061 + ... + 709862.

It is an arithmetic number, because the mean of its divisors is an integer number (5088356130).

Almost surely, 2^81389050623 is an apocalyptic number.

81389050623 is a deficient number, since it is larger than the sum of its proper divisors (40731496497).

81389050623 is a wasteful number, since it uses less digits than its factorization.

81389050623 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1294199 (or 1294196 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 45.

The spelling of 81389050623 in words is "eighty-one billion, three hundred eighty-nine million, fifty thousand, six hundred twenty-three".