21195973 has 4 divisors (see below), whose sum is σ = 21434220. Its totient is φ = 20957728.

The previous prime is 21195899. The next prime is 21195989. The reversal of 21195973 is 37959112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7491169 + 13704804 = 2737^2 + 3702^2 .

It is a cyclic number.

It is not a de Polignac number, because 21195973 - 2¹³ = 21187781 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 (21193973) 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, 118990 + ... + 119167.

It is an arithmetic number, because the mean of its divisors is an integer number (5358555).

Almost surely, 2^21195973 is an apocalyptic number.

It is an amenable number.

21195973 is a deficient number, since it is larger than the sum of its proper divisors (238247).

21195973 is an equidigital number, since it uses as much as digits as its factorization.

21195973 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 238246.

The product of its digits is 17010, while the sum is 37.

The square root of 21195973 is about 4603.9084482644. The cubic root of 21195973 is about 276.7479754891.

The spelling of 21195973 in words is "twenty-one million, one hundred ninety-five thousand, nine hundred seventy-three".