81245808 has 160 divisors (see below), whose sum is σ = 271173120. Its totient is φ = 22809600.

The previous prime is 81245789. The next prime is 81245809. The reversal of 81245808 is 80854218.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81245809) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 202408 + ... + 202808.

It is an arithmetic number, because the mean of its divisors is an integer number (1694832).

Almost surely, 2^81245808 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81245808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (135586560).

81245808 is an abundant number, since it is smaller than the sum of its proper divisors (189927312).

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

81245808 is a wasteful number, since it uses less digits than its factorization.

81245808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 492 (or 480 counting only the distinct ones).

The product of its (nonzero) digits is 20480, while the sum is 36.

The square root of 81245808 is about 9013.6456553384. The cubic root of 81245808 is about 433.1121037745.

The spelling of 81245808 in words is "eighty-one million, two hundred forty-five thousand, eight hundred eight".