81747039 has 16 divisors (see below), whose sum is σ = 119306880. Its totient is φ = 49376160.

The previous prime is 81747019. The next prime is 81747049. The reversal of 81747039 is 93074718.

It is not a de Polignac number, because 81747039 - 2¹⁷ = 81615967 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81746988 and 81747006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81747019) 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, 6097 + ... + 14165.

It is an arithmetic number, because the mean of its divisors is an integer number (7456680).

Almost surely, 2^81747039 is an apocalyptic number.

81747039 is a deficient number, since it is larger than the sum of its proper divisors (37559841).

81747039 is a wasteful number, since it uses less digits than its factorization.

81747039 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8390.

The product of its (nonzero) digits is 42336, while the sum is 39.

The square root of 81747039 is about 9041.4069148557. The cubic root of 81747039 is about 434.0009467866. Note that the first 3 decimals are identical.

The spelling of 81747039 in words is "eighty-one million, seven hundred forty-seven thousand, thirty-nine".