21421722373 has 4 divisors (see below), whose sum is σ = 21825905868. Its totient is φ = 21017538880.

The previous prime is 21421722347. The next prime is 21421722379. The reversal of 21421722373 is 37322712412.

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 13156548804 + 8265173569 = 114702^2 + 90913^2 .

It is a cyclic number.

It is not a de Polignac number, because 21421722373 - 2⁵ = 21421722341 is a prime.

It is a super-2 number, since 2×21421722373² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21421722379) 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, 202091668 + ... + 202091773.

It is an arithmetic number, because the mean of its divisors is an integer number (5456476467).

Almost surely, 2^21421722373 is an apocalyptic number.

It is an amenable number.

21421722373 is a deficient number, since it is larger than the sum of its proper divisors (404183495).

21421722373 is an equidigital number, since it uses as much as digits as its factorization.

21421722373 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 404183494.

The product of its digits is 28224, while the sum is 34.

The spelling of 21421722373 in words is "twenty-one billion, four hundred twenty-one million, seven hundred twenty-two thousand, three hundred seventy-three".