21545743 has 8 divisors (see below), whose sum is σ = 21902400. Its totient is φ = 21191808.

The previous prime is 21545723. The next prime is 21545759. The reversal of 21545743 is 34754512.

21545743 is nontrivially palindromic in base 12.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21545743 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 (21545723) 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, 20218 + ... + 21256.

It is an arithmetic number, because the mean of its divisors is an integer number (2737800).

Almost surely, 2^21545743 is an apocalyptic number.

21545743 is a deficient number, since it is larger than the sum of its proper divisors (356657).

21545743 is a wasteful number, since it uses less digits than its factorization.

21545743 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1361.

The product of its digits is 16800, while the sum is 31.

The square root of 21545743 is about 4641.7392214557. The cubic root of 21545743 is about 278.2619505311.

The spelling of 21545743 in words is "twenty-one million, five hundred forty-five thousand, seven hundred forty-three".