81311004747 has 36 divisors (see below), whose sum is σ = 138697394160. Its totient is φ = 44964577440.

The previous prime is 81311004739. The next prime is 81311004769. The reversal of 81311004747 is 74740011318.

81311004747 is a `hidden beast` number, since 81 + 3 + 1 + 100 + 474 + 7 = 666.

It is not a de Polignac number, because 81311004747 - 2³ = 81311004739 is a prime.

It is a super-2 number, since 2×81311004747² (a number of 23 digits) contains 22 as substring.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (81311005747) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 610972 + ... + 732057.

Almost surely, 2^81311004747 is an apocalyptic number.

81311004747 is a deficient number, since it is larger than the sum of its proper divisors (57386389413).

81311004747 is a wasteful number, since it uses less digits than its factorization.

81311004747 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1343104 (or 1343070 counting only the distinct ones).

The product of its (nonzero) digits is 18816, while the sum is 36.

The spelling of 81311004747 in words is "eighty-one billion, three hundred eleven million, four thousand, seven hundred forty-seven".