21192973 has 4 divisors (see below), whose sum is σ = 21214908. Its totient is φ = 21171040.

The previous prime is 21192967. The next prime is 21192989. The reversal of 21192973 is 37929112.

It is a happy number.

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 5368489 + 15824484 = 2317^2 + 3978^2 .

It is a cyclic number.

It is not a de Polignac number, because 21192973 - 2²¹ = 19095821 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 (21192953) 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, 9448 + ... + 11473.

It is an arithmetic number, because the mean of its divisors is an integer number (5303727).

Almost surely, 2^21192973 is an apocalyptic number.

It is an amenable number.

21192973 is a deficient number, since it is larger than the sum of its proper divisors (21935).

21192973 is a wasteful number, since it uses less digits than its factorization.

21192973 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21934.

The product of its digits is 6804, while the sum is 34.

The square root of 21192973 is about 4603.5826266072. The cubic root of 21192973 is about 276.7349182432.

The spelling of 21192973 in words is "twenty-one million, one hundred ninety-two thousand, nine hundred seventy-three".