21201543 has 24 divisors (see below), whose sum is σ = 33561216. Its totient is φ = 12790800.

The previous prime is 21201539. The next prime is 21201553. The reversal of 21201543 is 34510212.

21201543 is a `hidden beast` number, since 2 + 120 + 1 + 543 = 666.

It is not a de Polignac number, because 21201543 - 2² = 21201539 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201503) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 32446 + ... + 33092.

It is an arithmetic number, because the mean of its divisors is an integer number (1398384).

Almost surely, 2^21201543 is an apocalyptic number.

21201543 is a deficient number, since it is larger than the sum of its proper divisors (12359673).

21201543 is a wasteful number, since it uses less digits than its factorization.

21201543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 995 (or 992 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 21201543 is about 4604.5133293324. The cubic root of 21201543 is about 276.7722151755.

Adding to 21201543 its reverse (34510212), we get a palindrome (55711755).

It can be divided in two parts, 2120 and 1543, that added together give a palindrome (3663).

The spelling of 21201543 in words is "twenty-one million, two hundred one thousand, five hundred forty-three".