21411420 has 72 divisors (see below), whose sum is σ = 61696656. Its totient is φ = 5548032.

The previous prime is 21411407. The next prime is 21411431. The reversal of 21411420 is 2411412.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21411420.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 110844 + ... + 111036.

It is an arithmetic number, because the mean of its divisors is an integer number (856898).

Almost surely, 2^21411420 is an apocalyptic number.

21411420 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 21411420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30848328).

21411420 is an abundant number, since it is smaller than the sum of its proper divisors (40285236).

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

21411420 is a wasteful number, since it uses less digits than its factorization.

21411420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 291 (or 246 counting only the distinct ones).

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

The square root of 21411420 is about 4627.2475619962. The cubic root of 21411420 is about 277.6824868997.

Adding to 21411420 its reverse (2411412), we get a palindrome (23822832).

The spelling of 21411420 in words is "twenty-one million, four hundred eleven thousand, four hundred twenty".