21001312211 has 4 divisors (see below), whose sum is σ = 22910522424. Its totient is φ = 19092102000.

The previous prime is 21001312193. The next prime is 21001312231. The reversal of 21001312211 is 11221310012.

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

It is a cyclic number.

It is not a de Polignac number, because 21001312211 - 2²⁶ = 20934203347 is a prime.

It is a super-2 number, since 2×21001312211² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21001312231) 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, 954605090 + ... + 954605111.

It is an arithmetic number, because the mean of its divisors is an integer number (5727630606).

Almost surely, 2^21001312211 is an apocalyptic number.

21001312211 is a deficient number, since it is larger than the sum of its proper divisors (1909210213).

21001312211 is a wasteful number, since it uses less digits than its factorization.

21001312211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1909210212.

The product of its (nonzero) digits is 24, while the sum is 14.

Adding to 21001312211 its reverse (11221310012), we get a palindrome (32222622223).

The spelling of 21001312211 in words is "twenty-one billion, one million, three hundred twelve thousand, two hundred eleven".