21730943 has 8 divisors (see below), whose sum is σ = 23973936. Its totient is φ = 19569600.

The previous prime is 21730903. The next prime is 21730957. The reversal of 21730943 is 34903712.

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 21730943 - 2¹⁰ = 21729919 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 (21730903) 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, 19853 + ... + 20918.

It is an arithmetic number, because the mean of its divisors is an integer number (2996742).

Almost surely, 2^21730943 is an apocalyptic number.

21730943 is a deficient number, since it is larger than the sum of its proper divisors (2242993).

21730943 is a wasteful number, since it uses less digits than its factorization.

21730943 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40825.

The product of its (nonzero) digits is 4536, while the sum is 29.

The square root of 21730943 is about 4661.6459539523. The cubic root of 21730943 is about 279.0569592044.

The spelling of 21730943 in words is "twenty-one million, seven hundred thirty thousand, nine hundred forty-three".