20847320 has 64 divisors (see below), whose sum is σ = 51649920. Its totient is φ = 7524864.

The previous prime is 20847319. The next prime is 20847331. The reversal of 20847320 is 2374802.

It is a super-2 number, since 2×20847320² = 869221502364800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a self number, because there is not a number n which added to its sum of digits gives 20847320.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24014 + ... + 24866.

It is an arithmetic number, because the mean of its divisors is an integer number (807030).

Almost surely, 2^20847320 is an apocalyptic number.

20847320 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 20847320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25824960).

20847320 is an abundant number, since it is smaller than the sum of its proper divisors (30802600).

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

20847320 is a wasteful number, since it uses less digits than its factorization.

20847320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 924 (or 920 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 26.

The square root of 20847320 is about 4565.8865513720. The cubic root of 20847320 is about 275.2221675739. Note that the first 3 decimals are identical.

The spelling of 20847320 in words is "twenty million, eight hundred forty-seven thousand, three hundred twenty".