21228126 has 32 divisors (see below), whose sum is σ = 44582400. Its totient is φ = 6725664.

The previous prime is 21228101. The next prime is 21228133. The reversal of 21228126 is 62182212.

It is a junction number, because it is equal to n+sod(n) for n = 21228096 and 21228105.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27076 + ... + 27848.

It is an arithmetic number, because the mean of its divisors is an integer number (1393200).

Almost surely, 2^21228126 is an apocalyptic number.

21228126 is an abundant number, since it is smaller than the sum of its proper divisors (23354274).

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

21228126 is a wasteful number, since it uses less digits than its factorization.

21228126 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1000.

The product of its digits is 768, while the sum is 24.

The square root of 21228126 is about 4607.3990493553. The cubic root of 21228126 is about 276.8878413977.

The spelling of 21228126 in words is "twenty-one million, two hundred twenty-eight thousand, one hundred twenty-six".