21403543 has 8 divisors (see below), whose sum is σ = 24960800. Its totient is φ = 18345600.

The previous prime is 21403483. The next prime is 21403559. The reversal of 21403543 is 34530412.

It is a de Polignac number, because none of the positive numbers 2^k-21403543 is a prime.

It is a super-2 number, since 2×21403543² = 916223305905698, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21403243) 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, 30858 + ... + 31543.

It is an arithmetic number, because the mean of its divisors is an integer number (3120100).

Almost surely, 2^21403543 is an apocalyptic number.

21403543 is a deficient number, since it is larger than the sum of its proper divisors (3557257).

21403543 is an frugal number, since it uses more digits than its factorization.

21403543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62422 (or 62408 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 22.

The square root of 21403543 is about 4626.3963297582. The cubic root of 21403543 is about 277.6484307242.

Adding to 21403543 its reverse (34530412), we get a palindrome (55933955).

The spelling of 21403543 in words is "twenty-one million, four hundred three thousand, five hundred forty-three".