21415420 has 48 divisors (see below), whose sum is σ = 50012928. Its totient is φ = 7649280.

The previous prime is 21415417. The next prime is 21415423. The reversal of 21415420 is 2451412.

It is an interprime number because it is at equal distance from previous prime (21415417) and next prime (21415423).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21415423) 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, 6732 + ... + 9388.

It is an arithmetic number, because the mean of its divisors is an integer number (1041936).

Almost surely, 2^21415420 is an apocalyptic number.

21415420 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 21415420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25006464).

21415420 is an abundant number, since it is smaller than the sum of its proper divisors (28597508).

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

21415420 is a wasteful number, since it uses less digits than its factorization.

21415420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2710 (or 2708 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 19.

The square root of 21415420 is about 4627.6797642015. The cubic root of 21415420 is about 277.6997776848.

Adding to 21415420 its reverse (2451412), we get a palindrome (23866832).

The spelling of 21415420 in words is "twenty-one million, four hundred fifteen thousand, four hundred twenty".