21310943 has 4 divisors (see below), whose sum is σ = 21320328. Its totient is φ = 21301560.

The previous prime is 21310937. The next prime is 21310957. The reversal of 21310943 is 34901312.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21310943 - 2¹⁶ = 21245407 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 (21310043) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1088 + ... + 6618.

It is an arithmetic number, because the mean of its divisors is an integer number (5330082).

Almost surely, 2^21310943 is an apocalyptic number.

21310943 is a deficient number, since it is larger than the sum of its proper divisors (9385).

21310943 is an equidigital number, since it uses as much as digits as its factorization.

21310943 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9384.

The product of its (nonzero) digits is 648, while the sum is 23.

The square root of 21310943 is about 4616.3776925204. The cubic root of 21310943 is about 277.2474470872.

The spelling of 21310943 in words is "twenty-one million, three hundred ten thousand, nine hundred forty-three".