20213440 has 112 divisors (see below), whose sum is σ = 53510688. Its totient is φ = 7225344.

The previous prime is 20213437. The next prime is 20213443. The reversal of 20213440 is 4431202.

It is an interprime number because it is at equal distance from previous prime (20213437) and next prime (20213443).

It is a Harshad number since it is a multiple of its sum of digits (16).

It is not an unprimeable number, because it can be changed into a prime (20213443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 178824 + ... + 178936.

It is an arithmetic number, because the mean of its divisors is an integer number (477774).

Almost surely, 2^20213440 is an apocalyptic number.

20213440 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 20213440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26755344).

20213440 is an abundant number, since it is smaller than the sum of its proper divisors (33297248).

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

20213440 is a wasteful number, since it uses less digits than its factorization.

20213440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 186 (or 176 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 16.

The square root of 20213440 is about 4495.9359426042. The cubic root of 20213440 is about 272.4039557158.

Adding to 20213440 its reverse (4431202), we get a palindrome (24644642).

The spelling of 20213440 in words is "twenty million, two hundred thirteen thousand, four hundred forty".