81004340 has 48 divisors (see below), whose sum is σ = 175655424. Its totient is φ = 31363200.

The previous prime is 81004291. The next prime is 81004349. The reversal of 81004340 is 4340018.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a nialpdrome in base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81004349) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 81245 + ... + 82235.

It is an arithmetic number, because the mean of its divisors is an integer number (3659488).

Almost surely, 2^81004340 is an apocalyptic number.

It is an amenable number.

81004340 is an abundant number, since it is smaller than the sum of its proper divisors (94651084).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81004340 is a wasteful number, since it uses less digits than its factorization.

81004340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1128 (or 1126 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 81004340 is about 9000.2411078815. The cubic root of 81004340 is about 432.6825985630.

Adding to 81004340 its reverse (4340018), we get a palindrome (85344358).

The spelling of 81004340 in words is "eighty-one million, four thousand, three hundred forty".