20811420 has 144 divisors (see below), whose sum is σ = 73382400. Its totient is φ = 4675968.

The previous prime is 20811419. The next prime is 20811421. The reversal of 20811420 is 2411802.

It is an interprime number because it is at equal distance from previous prime (20811419) and next prime (20811421).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 20811393 and 20811402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20811421) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 104481 + ... + 104679.

It is an arithmetic number, because the mean of its divisors is an integer number (509600).

Almost surely, 2^20811420 is an apocalyptic number.

20811420 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 20811420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36691200).

20811420 is an abundant number, since it is smaller than the sum of its proper divisors (52570980).

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

20811420 is a wasteful number, since it uses less digits than its factorization.

20811420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 304 (or 299 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

The square root of 20811420 is about 4561.9535289172. The cubic root of 20811420 is about 275.0640952528.

It can be divided in two parts, 208 and 11420, that added together give a triangular number (11628 = T₁₅₂).

The spelling of 20811420 in words is "twenty million, eight hundred eleven thousand, four hundred twenty".