20021310 has 64 divisors (see below), whose sum is σ = 55252800. Its totient is φ = 5152896.

The previous prime is 20021303. The next prime is 20021311. The reversal of 20021310 is 1312002.

It is a happy number.

It is a super-2 number, since 2×20021310² = 801705708232200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 20021292 and 20021301.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20021311) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6552 + ... + 9108.

It is an arithmetic number, because the mean of its divisors is an integer number (863325).

Almost surely, 2^20021310 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20021310, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27626400).

20021310 is an abundant number, since it is smaller than the sum of its proper divisors (35231490).

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

20021310 is a wasteful number, since it uses less digits than its factorization.

20021310 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2602 (or 2596 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 9.

The square root of 20021310 is about 4474.5178511209. The cubic root of 20021310 is about 271.5381345049.

Adding to 20021310 its reverse (1312002), we get a palindrome (21333312).

The spelling of 20021310 in words is "twenty million, twenty-one thousand, three hundred ten".