21000001213 has 16 divisors (see below), whose sum is σ = 23210893440. Its totient is φ = 18898164736.

The previous prime is 21000001201. The next prime is 21000001249. The reversal of 21000001213 is 31210000012.

It is a cyclic number.

It is not a de Polignac number, because 21000001213 - 2⁹ = 21000000701 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21000001213.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000001013) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1199106 + ... + 1216492.

It is an arithmetic number, because the mean of its divisors is an integer number (1450680840).

Almost surely, 2^21000001213 is an apocalyptic number.

21000001213 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21000001213 is a deficient number, since it is larger than the sum of its proper divisors (2210892227).

21000001213 is a wasteful number, since it uses less digits than its factorization.

21000001213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20516.

The product of its (nonzero) digits is 12, while the sum is 10.

Adding to 21000001213 its reverse (31210000012), we get a palindrome (52210001225).

The spelling of 21000001213 in words is "twenty-one billion, one thousand, two hundred thirteen".