21099543 has 8 divisors (see below), whose sum is σ = 28819056. Its totient is φ = 13723200.

The previous prime is 21099539. The next prime is 21099563. The reversal of 21099543 is 34599012.

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

It is not a de Polignac number, because 21099543 - 2² = 21099539 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21099503) 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, 85648 + ... + 85893.

It is an arithmetic number, because the mean of its divisors is an integer number (3602382).

Almost surely, 2^21099543 is an apocalyptic number.

21099543 is a deficient number, since it is larger than the sum of its proper divisors (7719513).

21099543 is a wasteful number, since it uses less digits than its factorization.

21099543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 171585.

The product of its (nonzero) digits is 9720, while the sum is 33.

The square root of 21099543 is about 4593.4238863837. The cubic root of 21099543 is about 276.3276538245.

The spelling of 21099543 in words is "twenty-one million, ninety-nine thousand, five hundred forty-three".