21211320021 has 8 divisors (see below), whose sum is σ = 28408584960. Its totient is φ = 14077467552.

The previous prime is 21211319989. The next prime is 21211320037. The reversal of 21211320021 is 12002311212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21211320021 - 2⁵ = 21211319989 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211320421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15852336 + ... + 15853673.

It is an arithmetic number, because the mean of its divisors is an integer number (3551073120).

Almost surely, 2^21211320021 is an apocalyptic number.

It is an amenable number.

21211320021 is a deficient number, since it is larger than the sum of its proper divisors (7197264939).

21211320021 is a wasteful number, since it uses less digits than its factorization.

21211320021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31706235.

The product of its (nonzero) digits is 48, while the sum is 15.

Adding to 21211320021 its reverse (12002311212), we get a palindrome (33213631233).

The spelling of 21211320021 in words is "twenty-one billion, two hundred eleven million, three hundred twenty thousand, twenty-one".