21034340 has 12 divisors (see below), whose sum is σ = 44172156. Its totient is φ = 8413728.

The previous prime is 21034331. The next prime is 21034357. The reversal of 21034340 is 4343012.

It can be written as a sum of positive squares in 2 ways, for example, as 10588516 + 10445824 = 3254^2 + 3232^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 525839 + ... + 525878.

It is an arithmetic number, because the mean of its divisors is an integer number (3681013).

Almost surely, 2^21034340 is an apocalyptic number.

21034340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21034340 is an abundant number, since it is smaller than the sum of its proper divisors (23137816).

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

21034340 is a wasteful number, since it uses less digits than its factorization.

21034340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1051726 (or 1051724 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 17.

The square root of 21034340 is about 4586.3209656543. The cubic root of 21034340 is about 276.0427190055.

Adding to 21034340 its reverse (4343012), we get a palindrome (25377352).

The spelling of 21034340 in words is "twenty-one million, thirty-four thousand, three hundred forty".