21210110001 has 24 divisors (see below), whose sum is σ = 32413043520. Its totient is φ = 13327838496.

The previous prime is 21210109969. The next prime is 21210110003. The reversal of 21210110001 is 10001101212.

It is a happy number.

It is not a de Polignac number, because 21210110001 - 2⁵ = 21210109969 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is not an unprimeable number, because it can be changed into a prime (21210110003) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 281125 + ... + 348498.

It is an arithmetic number, because the mean of its divisors is an integer number (1350543480).

Almost surely, 2^21210110001 is an apocalyptic number.

It is an amenable number.

21210110001 is a deficient number, since it is larger than the sum of its proper divisors (11202933519).

21210110001 is a wasteful number, since it uses less digits than its factorization.

21210110001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 629845 (or 629842 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

Adding to 21210110001 its reverse (10001101212), we get a palindrome (31211211213).

The spelling of 21210110001 in words is "twenty-one billion, two hundred ten million, one hundred ten thousand, one".