21011340 has 96 divisors (see below), whose sum is σ = 70801920. Its totient is φ = 4548096.

The previous prime is 21011327. The next prime is 21011357. The reversal of 21011340 is 4311012.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (12).

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, 6664 + ... + 9296.

It is an arithmetic number, because the mean of its divisors is an integer number (737520).

Almost surely, 2^21011340 is an apocalyptic number.

21011340 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 21011340, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35400960).

21011340 is an abundant number, since it is smaller than the sum of its proper divisors (49790580).

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

21011340 is a wasteful number, since it uses less digits than its factorization.

21011340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2671 (or 2669 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 21011340 is about 4583.8128234037. The cubic root of 21011340 is about 275.9420693371.

Adding to 21011340 its reverse (4311012), we get a palindrome (25322352).

The spelling of 21011340 in words is "twenty-one million, eleven thousand, three hundred forty".