21020343 has 16 divisors (see below), whose sum is σ = 28803840. Its totient is φ = 13630464.

The previous prime is 21020339. The next prime is 21020353. The reversal of 21020343 is 34302012.

It is not a de Polignac number, because 21020343 - 2² = 21020339 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020303) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17655 + ... + 18807.

It is an arithmetic number, because the mean of its divisors is an integer number (1800240).

Almost surely, 2^21020343 is an apocalyptic number.

21020343 is a deficient number, since it is larger than the sum of its proper divisors (7783497).

21020343 is a wasteful number, since it uses less digits than its factorization.

21020343 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1318.

The product of its (nonzero) digits is 144, while the sum is 15.

The square root of 21020343 is about 4584.7947609462. The cubic root of 21020343 is about 275.9814758624.

Adding to 21020343 its reverse (34302012), we get a palindrome (55322355).

The spelling of 21020343 in words is "twenty-one million, twenty thousand, three hundred forty-three".