21201212202101 has 4 divisors (see below), whose sum is σ = 21203901695232. Its totient is φ = 21198522708972.

The previous prime is 21201212202089. The next prime is 21201212202133. The reversal of 21201212202101 is 10120221210212.

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 a de Polignac number, because none of the positive numbers 2^k-21201212202101 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21201212202101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201212202301) 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, 1344734741 + ... + 1344750506.

It is an arithmetic number, because the mean of its divisors is an integer number (5300975423808).

Almost surely, 2^{21201212202101} is an apocalyptic number.

It is an amenable number.

21201212202101 is a deficient number, since it is larger than the sum of its proper divisors (2689493131).

21201212202101 is an equidigital number, since it uses as much as digits as its factorization.

21201212202101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2689493130.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 21201212202101 its reverse (10120221210212), we get a palindrome (31321433412313).

The spelling of 21201212202101 in words is "twenty-one trillion, two hundred one billion, two hundred twelve million, two hundred two thousand, one hundred one".