21707543 has 12 divisors (see below), whose sum is σ = 25644888. Its totient is φ = 18214560.

The previous prime is 21707537. The next prime is 21707549. The reversal of 21707543 is 34570712.

It is an interprime number because it is at equal distance from previous prime (21707537) and next prime (21707549).

It is not a de Polignac number, because 21707543 - 2¹⁰ = 21706519 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 (21707549) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3980 + ... + 7697.

It is an arithmetic number, because the mean of its divisors is an integer number (2137074).

Almost surely, 2^21707543 is an apocalyptic number.

21707543 is a deficient number, since it is larger than the sum of its proper divisors (3937345).

21707543 is a wasteful number, since it uses less digits than its factorization.

21707543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11714 (or 11701 counting only the distinct ones).

The product of its (nonzero) digits is 5880, while the sum is 29.

The square root of 21707543 is about 4659.1354348205. The cubic root of 21707543 is about 278.9567598701.

The spelling of 21707543 in words is "twenty-one million, seven hundred seven thousand, five hundred forty-three".