27821220 has 72 divisors (see below), whose sum is σ = 90627264. Its totient is φ = 6358464.

The previous prime is 27821173. The next prime is 27821221. The reversal of 27821220 is 2212872.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (27821221) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1792 + ... + 7671.

It is an arithmetic number, because the mean of its divisors is an integer number (1258712).

Almost surely, 2^27821220 is an apocalyptic number.

27821220 is a gapful number since it is divisible by the number (20) 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 27821220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45313632).

27821220 is an abundant number, since it is smaller than the sum of its proper divisors (62806044).

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

27821220 is a wasteful number, since it uses less digits than its factorization.

27821220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9489 (or 9480 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 24.

The square root of 27821220 is about 5274.5824479289. The cubic root of 27821220 is about 303.0112294197.

The spelling of 27821220 in words is "twenty-seven million, eight hundred twenty-one thousand, two hundred twenty".