21701973 has 4 divisors (see below), whose sum is σ = 28935968. Its totient is φ = 14467980.

The previous prime is 21701959. The next prime is 21701987. The reversal of 21701973 is 37910712.

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 an interprime number because it is at equal distance from previous prime (21701959) and next prime (21701987).

It is not a de Polignac number, because 21701973 - 2⁵ = 21701941 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21701973.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21701473) 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, 3616993 + ... + 3616998.

It is an arithmetic number, because the mean of its divisors is an integer number (7233992).

Almost surely, 2^21701973 is an apocalyptic number.

It is an amenable number.

21701973 is a deficient number, since it is larger than the sum of its proper divisors (7233995).

21701973 is an equidigital number, since it uses as much as digits as its factorization.

21701973 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7233994.

The product of its (nonzero) digits is 2646, while the sum is 30.

The square root of 21701973 is about 4658.5376460859. The cubic root of 21701973 is about 278.9328983938.

The spelling of 21701973 in words is "twenty-one million, seven hundred one thousand, nine hundred seventy-three".