20021340 has 48 divisors (see below), whose sum is σ = 56575008. Its totient is φ = 5289984.

The previous prime is 20021327. The next prime is 20021341. The reversal of 20021340 is 4312002.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20021341) 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, 5304 + ... + 8256.

It is an arithmetic number, because the mean of its divisors is an integer number (1178646).

Almost surely, 2^20021340 is an apocalyptic number.

20021340 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 20021340, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28287504).

20021340 is an abundant number, since it is smaller than the sum of its proper divisors (36553668).

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

20021340 is a wasteful number, since it uses less digits than its factorization.

20021340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3078 (or 3076 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 12.

The square root of 20021340 is about 4474.5212034362. The cubic root of 20021340 is about 271.5382701293.

Adding to 20021340 its reverse (4312002), we get a palindrome (24333342).

The spelling of 20021340 in words is "twenty million, twenty-one thousand, three hundred forty".