81303040 has 160 divisors (see below), whose sum is σ = 240609600. Its totient is φ = 25657344.

The previous prime is 81303029. The next prime is 81303043. The reversal of 81303040 is 4030318.

It is a tau number, because it is divible by the number of its divisors (160).

It is a super-2 number, since 2×81303040² = 13220368626483200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81302999 and 81303017.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81303043) 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, 232786 + ... + 233134.

It is an arithmetic number, because the mean of its divisors is an integer number (1503810).

Almost surely, 2^81303040 is an apocalyptic number.

81303040 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81303040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (120304800).

81303040 is an abundant number, since it is smaller than the sum of its proper divisors (159306560).

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

81303040 is a wasteful number, since it uses less digits than its factorization.

81303040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 392 (or 376 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 81303040 is about 9016.8198385018. The cubic root of 81303040 is about 433.2137789844.

Adding to 81303040 its reverse (4030318), we get a palindrome (85333358).

The spelling of 81303040 in words is "eighty-one million, three hundred three thousand, forty".