21012210001 has 6 divisors (see below), whose sum is σ = 22320929270. Its totient is φ = 19776197376.

The previous prime is 21012209951. The next prime is 21012210013. The reversal of 21012210001 is 10001221012.

It can be written as a sum of positive squares in 3 ways, for example, as 9632441025 + 11379768976 = 98145^2 + 106676^2 .

It is not a de Polignac number, because 21012210001 - 2¹³ = 21012201809 is a prime.

It is a super-2 number, since 2×21012210001² (a number of 21 digits) contains 22 as substring.

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 21012210001.

It is not an unprimeable number, because it can be changed into a prime (21012270001) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 36353016 + ... + 36353593.

Almost surely, 2^21012210001 is an apocalyptic number.

It is an amenable number.

21012210001 is a deficient number, since it is larger than the sum of its proper divisors (1308719269).

21012210001 is an equidigital number, since it uses as much as digits as its factorization.

21012210001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72706643 (or 72706626 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 21012210001 its reverse (10001221012), we get a palindrome (31013431013).

The spelling of 21012210001 in words is "twenty-one billion, twelve million, two hundred ten thousand, one".