21703973 has 4 divisors (see below), whose sum is σ = 22647648. Its totient is φ = 20760300.

The previous prime is 21703967. The next prime is 21703993. The reversal of 21703973 is 37930712.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21703973 - 2¹⁰ = 21702949 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 (21703993) 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, 471803 + ... + 471848.

It is an arithmetic number, because the mean of its divisors is an integer number (5661912).

Almost surely, 2^21703973 is an apocalyptic number.

21703973 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21703973 is a deficient number, since it is larger than the sum of its proper divisors (943675).

21703973 is an equidigital number, since it uses as much as digits as its factorization.

21703973 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 943674.

The product of its (nonzero) digits is 7938, while the sum is 32.

The square root of 21703973 is about 4658.7523007775. The cubic root of 21703973 is about 278.9414667186.

The spelling of 21703973 in words is "twenty-one million, seven hundred three thousand, nine hundred seventy-three".