21334440 has 32 divisors (see below), whose sum is σ = 64003680. Its totient is φ = 5689152.

The previous prime is 21334433. The next prime is 21334447. The reversal of 21334440 is 4443312.

It is an interprime number because it is at equal distance from previous prime (21334433) and next prime (21334447).

It is a super-2 number, since 2×21334440² = 910316660227200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21334447) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 88774 + ... + 89013.

It is an arithmetic number, because the mean of its divisors is an integer number (2000115).

Almost surely, 2^21334440 is an apocalyptic number.

21334440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21334440 is an abundant number, since it is smaller than the sum of its proper divisors (42669240).

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

21334440 is a wasteful number, since it uses less digits than its factorization.

21334440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 177801 (or 177797 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 21.

The square root of 21334440 is about 4618.9219521442. The cubic root of 21334440 is about 277.3493054061.

Adding to 21334440 its reverse (4443312), we get a palindrome (25777752).

The spelling of 21334440 in words is "twenty-one million, three hundred thirty-four thousand, four hundred forty".