20021040 has 320 divisors, whose sum is σ = 79994880. Its totient is φ = 4561920.

The previous prime is 20021021. The next prime is 20021059. The reversal of 20021040 is 4012002.

It is an interprime number because it is at equal distance from previous prime (20021021) and next prime (20021059).

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

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 63 ways as a sum of consecutive naturals, for example, 645825 + ... + 645855.

It is an arithmetic number, because the mean of its divisors is an integer number (249984).

Almost surely, 2^20021040 is an apocalyptic number.

20021040 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 20021040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39997440).

20021040 is an abundant number, since it is smaller than the sum of its proper divisors (59973840).

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

20021040 is a wasteful number, since it uses less digits than its factorization.

20021040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89 (or 77 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 9.

The square root of 20021040 is about 4474.4876801708. The cubic root of 20021040 is about 271.5369138783.

Adding to 20021040 its reverse (4012002), we get a palindrome (24033042).

The spelling of 20021040 in words is "twenty million, twenty-one thousand, forty".