20021280 has 96 divisors (see below), whose sum is σ = 64338624. Its totient is φ = 5231616.

The previous prime is 20021263. The next prime is 20021297. The reversal of 20021280 is 8212002.

It is an interprime number because it is at equal distance from previous prime (20021263) and next prime (20021297).

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25047 + ... + 25833.

It is an arithmetic number, because the mean of its divisors is an integer number (670194).

Almost surely, 2^20021280 is an apocalyptic number.

20021280 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 20021280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32169312).

20021280 is an abundant number, since it is smaller than the sum of its proper divisors (44317344).

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

20021280 is a wasteful number, since it uses less digits than its factorization.

20021280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 858 (or 850 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

The square root of 20021280 is about 4474.5144988032. The cubic root of 20021280 is about 271.5379988802.

Adding to 20021280 its reverse (8212002), we get a palindrome (28233282).

It can be divided in two parts, 20021 and 280, that added together give a triangular number (20301 = T₂₀₁).

The spelling of 20021280 in words is "twenty million, twenty-one thousand, two hundred eighty".