21231212101 has 8 divisors (see below), whose sum is σ = 23377784544. Its totient is φ = 19120716720.

The previous prime is 21231212083. The next prime is 21231212131. The reversal of 21231212101 is 10121213212.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21231212101 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 (21231212131) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9018030 + ... + 9020383.

It is an arithmetic number, because the mean of its divisors is an integer number (2922223068).

Almost surely, 2^21231212101 is an apocalyptic number.

It is an amenable number.

21231212101 is a deficient number, since it is larger than the sum of its proper divisors (2146572443).

21231212101 is a wasteful number, since it uses less digits than its factorization.

21231212101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18038531.

The product of its (nonzero) digits is 48, while the sum is 16.

Adding to 21231212101 its reverse (10121213212), we get a palindrome (31352425313).

It can be divided in two parts, 21231 and 212101, that added together give a palindrome (233332).

The spelling of 21231212101 in words is "twenty-one billion, two hundred thirty-one million, two hundred twelve thousand, one hundred one".