81049040 has 40 divisors (see below), whose sum is σ = 188821248. Its totient is φ = 32353920.

The previous prime is 81049039. The next prime is 81049049. The reversal of 81049040 is 4094018.

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81049049) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 65225 + ... + 66455.

Almost surely, 2^81049040 is an apocalyptic number.

81049040 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81049040 is an abundant number, since it is smaller than the sum of its proper divisors (107772208).

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

81049040 is a wasteful number, since it uses less digits than its factorization.

81049040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2067 (or 2061 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 26.

The square root of 81049040 is about 9002.7240322027. The cubic root of 81049040 is about 432.7621718948.

The spelling of 81049040 in words is "eighty-one million, forty-nine thousand, forty".