21213222131 has 4 divisors (see below), whose sum is σ = 21213537072. Its totient is φ = 21212907192.

The previous prime is 21213222127. The next prime is 21213222137. The reversal of 21213222131 is 13122231212.

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 21213222131 - 2² = 21213222127 is a prime.

It is a super-2 number, since 2×21213222131² (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 (21213222137) 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, 11060 + ... + 206273.

It is an arithmetic number, because the mean of its divisors is an integer number (5303384268).

Almost surely, 2^21213222131 is an apocalyptic number.

21213222131 is a deficient number, since it is larger than the sum of its proper divisors (314941).

21213222131 is an equidigital number, since it uses as much as digits as its factorization.

21213222131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 314940.

The product of its digits is 288, while the sum is 20.

Adding to 21213222131 its reverse (13122231212), we get a palindrome (34335453343).

The spelling of 21213222131 in words is "twenty-one billion, two hundred thirteen million, two hundred twenty-two thousand, one hundred thirty-one".