21227940 has 96 divisors (see below), whose sum is σ = 69552000. Its totient is φ = 5360256.

The previous prime is 21227933. The next prime is 21227977. The reversal of 21227940 is 4972212.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 9226 + ... + 11294.

It is an arithmetic number, because the mean of its divisors is an integer number (724500).

Almost surely, 2^21227940 is an apocalyptic number.

21227940 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 21227940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34776000).

21227940 is an abundant number, since it is smaller than the sum of its proper divisors (48324060).

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

21227940 is a wasteful number, since it uses less digits than its factorization.

21227940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2106 (or 2098 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 21227940 is about 4607.3788643870. The cubic root of 21227940 is about 276.8870327019.

The spelling of 21227940 in words is "twenty-one million, two hundred twenty-seven thousand, nine hundred forty".