81749837 has 24 divisors (see below), whose sum is σ = 95407200. Its totient is φ = 69437088.

The previous prime is 81749831. The next prime is 81749839. The reversal of 81749837 is 73894718.

It is not a de Polignac number, because 81749837 - 2¹⁰ = 81748813 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81749791 and 81749800.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81749831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 456614 + ... + 456792.

It is an arithmetic number, because the mean of its divisors is an integer number (3975300).

Almost surely, 2^81749837 is an apocalyptic number.

It is an amenable number.

81749837 is a deficient number, since it is larger than the sum of its proper divisors (13657363).

81749837 is a wasteful number, since it uses less digits than its factorization.

81749837 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 297 (or 254 counting only the distinct ones).

The product of its digits is 338688, while the sum is 47.

The square root of 81749837 is about 9041.5616460875. The cubic root of 81749837 is about 434.0058983250.

The spelling of 81749837 in words is "eighty-one million, seven hundred forty-nine thousand, eight hundred thirty-seven".