820945280 has 64 divisors (see below), whose sum is σ = 1974581280. Its totient is φ = 326369280.

The previous prime is 820945277. The next prime is 820945291. The reversal of 820945280 is 82549028.

It is a tau number, because it is divible by the number of its divisors (64).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 103040 + ... + 110720.

Almost surely, 2^820945280 is an apocalyptic number.

820945280 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 820945280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (987290640).

820945280 is an abundant number, since it is smaller than the sum of its proper divisors (1153636000).

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

820945280 is a wasteful number, since it uses less digits than its factorization.

820945280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7867 (or 7855 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 38.

The square root of 820945280 is about 28652.1426772938. The cubic root of 820945280 is about 936.3496879301.

The spelling of 820945280 in words is "eight hundred twenty million, nine hundred forty-five thousand, two hundred eighty".