81000729387 has 12 divisors (see below), whose sum is σ = 117014756040. Its totient is φ = 53994162048.

The previous prime is 81000729367. The next prime is 81000729401. The reversal of 81000729387 is 78392700018.

It is not a de Polignac number, because 81000729387 - 2⁶ = 81000729323 is a prime.

It is a super-2 number, since 2×81000729387² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81000729367) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 445233 + ... + 600194.

It is an arithmetic number, because the mean of its divisors is an integer number (9751229670).

Almost surely, 2^81000729387 is an apocalyptic number.

81000729387 is a deficient number, since it is larger than the sum of its proper divisors (36014026653).

81000729387 is a wasteful number, since it uses less digits than its factorization.

81000729387 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1054042 (or 1054039 counting only the distinct ones).

The product of its (nonzero) digits is 169344, while the sum is 45.

The spelling of 81000729387 in words is "eighty-one billion, seven hundred twenty-nine thousand, three hundred eighty-seven".