21201420 has 48 divisors (see below), whose sum is σ = 59609088. Its totient is φ = 5630400.

The previous prime is 21201419. The next prime is 21201421. The reversal of 21201420 is 2410212.

It is an interprime number because it is at equal distance from previous prime (21201419) and next prime (21201421).

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 21201396 and 21201405.

It is not an unprimeable number, because it can be changed into a prime (21201421) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17845 + ... + 18995.

It is an arithmetic number, because the mean of its divisors is an integer number (1241856).

Almost surely, 2^21201420 is an apocalyptic number.

21201420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is a pronic number, being equal to 4604×4605.

It is an amenable number.

21201420 is an abundant number, since it is smaller than the sum of its proper divisors (38407668).

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

21201420 is a wasteful number, since it uses less digits than its factorization.

21201420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1470 (or 1468 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 12.

The square root of 21201420 is about 4604.4999728526. The cubic root of 21201420 is about 276.7716799464.

Adding to 21201420 its reverse (2410212), we get a palindrome (23611632).

The spelling of 21201420 in words is "twenty-one million, two hundred one thousand, four hundred twenty".