21227420 has 24 divisors (see below), whose sum is σ = 46116000. Its totient is φ = 8197952.

The previous prime is 21227419. The next prime is 21227447. The reversal of 21227420 is 2472212.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 21227392 and 21227401.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17720 + ... + 18879.

It is an arithmetic number, because the mean of its divisors is an integer number (1921500).

Almost surely, 2^21227420 is an apocalyptic number.

21227420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21227420 is an abundant number, since it is smaller than the sum of its proper divisors (24888580).

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

21227420 is a wasteful number, since it uses less digits than its factorization.

21227420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36637 (or 36635 counting only the distinct ones).

The product of its (nonzero) digits is 448, while the sum is 20.

The square root of 21227420 is about 4607.3224328236. The cubic root of 21227420 is about 276.8847718068.

Adding to 21227420 its reverse (2472212), we get a palindrome (23699632).

The spelling of 21227420 in words is "twenty-one million, two hundred twenty-seven thousand, four hundred twenty".