21343340 has 12 divisors (see below), whose sum is σ = 44821056. Its totient is φ = 8537328.

The previous prime is 21343337. The next prime is 21343363. The reversal of 21343340 is 4334312.

It is a Harshad number since it is a multiple of its sum of digits (20), and also a Moran number because the ratio is a prime number: 1067167 = 21343340 / (2 + 1 + 3 + 4 + 3 + 3 + 4 + 0).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 533564 + ... + 533603.

It is an arithmetic number, because the mean of its divisors is an integer number (3735088).

Almost surely, 2^21343340 is an apocalyptic number.

21343340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21343340 is an abundant number, since it is smaller than the sum of its proper divisors (23477716).

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

21343340 is a wasteful number, since it uses less digits than its factorization.

21343340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1067176 (or 1067174 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 20.

The square root of 21343340 is about 4619.8852799610. The cubic root of 21343340 is about 277.3878669316.

Adding to 21343340 its reverse (4334312), we get a palindrome (25677652).

Subtracting from 21343340 its reverse (4334312), we obtain a triangular number (17009028 = T₅₈₃₂).

The spelling of 21343340 in words is "twenty-one million, three hundred forty-three thousand, three hundred forty".