21212202001 has 4 divisors (see below), whose sum is σ = 21230164404. Its totient is φ = 21194239600.

The previous prime is 21212201963. The next prime is 21212202041. The reversal of 21212202001 is 10020221212.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 18123621376 + 3088580625 = 134624^2 + 55575^2 .

It is a cyclic number.

It is not a de Polignac number, because 21212202001 - 2⁹ = 21212201489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21212202041) 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, 8979430 + ... + 8981791.

It is an arithmetic number, because the mean of its divisors is an integer number (5307541101).

Almost surely, 2^21212202001 is an apocalyptic number.

It is an amenable number.

21212202001 is a deficient number, since it is larger than the sum of its proper divisors (17962403).

21212202001 is a wasteful number, since it uses less digits than its factorization.

21212202001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17962402.

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21212202001 its reverse (10020221212), we get a palindrome (31232423213).

The spelling of 21212202001 in words is "twenty-one billion, two hundred twelve million, two hundred two thousand, one".