21101002002 has 24 divisors (see below), whose sum is σ = 45767667036. Its totient is φ = 7026155136.

The previous prime is 21101001947. The next prime is 21101002019. The reversal of 21101002002 is 20020010112.

It can be written as a sum of positive squares in 2 ways, for example, as 18528382161 + 2572619841 = 136119^2 + 50721^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 608683 + ... + 642414.

Almost surely, 2^21101002002 is an apocalyptic number.

21101002002 is an abundant number, since it is smaller than the sum of its proper divisors (24666665034).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21101002002 is a wasteful number, since it uses less digits than its factorization.

21101002002 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1252042 (or 1252039 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 21101002002 its reverse (20020010112), we get a palindrome (41121012114).

The spelling of 21101002002 in words is "twenty-one billion, one hundred one million, two thousand, two".