21212010101 has 4 divisors (see below), whose sum is σ = 21213489600. Its totient is φ = 21210530604.

The previous prime is 21212010097. The next prime is 21212010119. The reversal of 21212010101 is 10101021212.

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 21212010101 - 2² = 21212010097 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 (21212010161) 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, 718031 + ... + 746988.

It is an arithmetic number, because the mean of its divisors is an integer number (5303372400).

Almost surely, 2^21212010101 is an apocalyptic number.

It is an amenable number.

21212010101 is a deficient number, since it is larger than the sum of its proper divisors (1479499).

21212010101 is a wasteful number, since it uses less digits than its factorization.

21212010101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1479498.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21212010101 its reverse (10101021212), we get a palindrome (31313031313).

The spelling of 21212010101 in words is "twenty-one billion, two hundred twelve million, ten thousand, one hundred one".