21631543 has 8 divisors (see below), whose sum is σ = 22176000. Its totient is φ = 21094008.

The previous prime is 21631541. The next prime is 21631573. The reversal of 21631543 is 34513612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21631543 - 2¹ = 21631541 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21631541) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 4908 + ... + 8206.

It is an arithmetic number, because the mean of its divisors is an integer number (2772000).

Almost surely, 2^21631543 is an apocalyptic number.

21631543 is a deficient number, since it is larger than the sum of its proper divisors (544457).

21631543 is an equidigital number, since it uses as much as digits as its factorization.

21631543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3461.

The product of its digits is 2160, while the sum is 25.

The square root of 21631543 is about 4650.9722639465. The cubic root of 21631543 is about 278.6308285592.

The spelling of 21631543 in words is "twenty-one million, six hundred thirty-one thousand, five hundred forty-three".