21201219973 has 4 divisors (see below), whose sum is σ = 21517656160. Its totient is φ = 20884783788.

The previous prime is 21201219953. The next prime is 21201219997. The reversal of 21201219973 is 37991210212.

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 21201219973 - 2¹³ = 21201211781 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 (21201219953) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 158217993 + ... + 158218126.

It is an arithmetic number, because the mean of its divisors is an integer number (5379414040).

Almost surely, 2^21201219973 is an apocalyptic number.

It is an amenable number.

21201219973 is a deficient number, since it is larger than the sum of its proper divisors (316436187).

21201219973 is an equidigital number, since it uses as much as digits as its factorization.

21201219973 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 316436186.

The product of its (nonzero) digits is 13608, while the sum is 37.

The spelling of 21201219973 in words is "twenty-one billion, two hundred one million, two hundred nineteen thousand, nine hundred seventy-three".