811220880 has 80 divisors (see below), whose sum is σ = 2523052800. Its totient is φ = 215614464.

The previous prime is 811220869. The next prime is 811220887. The reversal of 811220880 is 88022118.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×811220880² = 1316158632295948800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is not an unprimeable number, because it can be changed into a prime (811220887) 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, 69721 + ... + 80519.

It is an arithmetic number, because the mean of its divisors is an integer number (31538160).

Almost surely, 2^811220880 is an apocalyptic number.

811220880 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 811220880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1261526400).

811220880 is an abundant number, since it is smaller than the sum of its proper divisors (1711831920).

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

811220880 is a wasteful number, since it uses less digits than its factorization.

811220880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11128 (or 11122 counting only the distinct ones).

The product of its (nonzero) digits is 2048, while the sum is 30.

The square root of 811220880 is about 28481.9395406984. The cubic root of 811220880 is about 932.6378571760.

Adding to 811220880 its reverse (88022118), we get a palindrome (899242998).

The spelling of 811220880 in words is "eight hundred eleven million, two hundred twenty thousand, eight hundred eighty".