811537920 has 320 divisors, whose sum is σ = 2946240000. Its totient is φ = 211673088.

The previous prime is 811537901. The next prime is 811537921. The reversal of 811537920 is 29735118.

It is a tau number, because it is divible by the number of its divisors (320).

It is a super-3 number, since 3×811537920³ (a number of 28 digits) contains 333 as substring.

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 (811537921) 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 31 ways as a sum of consecutive naturals, for example, 4077981 + ... + 4078179.

It is an arithmetic number, because the mean of its divisors is an integer number (9207000).

Almost surely, 2^811537920 is an apocalyptic number.

811537920 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 811537920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1473120000).

811537920 is an abundant number, since it is smaller than the sum of its proper divisors (2134702080).

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

811537920 is a wasteful number, since it uses less digits than its factorization.

811537920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 290 (or 268 counting only the distinct ones).

The product of its (nonzero) digits is 15120, while the sum is 36.

The square root of 811537920 is about 28487.5046292230. The cubic root of 811537920 is about 932.7593386789.

The spelling of 811537920 in words is "eight hundred eleven million, five hundred thirty-seven thousand, nine hundred twenty".