21201001002 has 96 divisors (see below), whose sum is σ = 51336529920. Its totient is φ = 6284113920.

The previous prime is 21201000991. The next prime is 21201001013. The reversal of 21201001002 is 20010010212.

It is an interprime number because it is at equal distance from previous prime (21201000991) and next prime (21201001013).

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 47 ways as a sum of consecutive naturals, for example, 2222002 + ... + 2231522.

It is an arithmetic number, because the mean of its divisors is an integer number (534755520).

Almost surely, 2^21201001002 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21201001002, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25668264960).

21201001002 is an abundant number, since it is smaller than the sum of its proper divisors (30135528918).

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

21201001002 is a wasteful number, since it uses less digits than its factorization.

21201001002 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9948 (or 9945 counting only the distinct ones).

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

Adding to 21201001002 its reverse (20010010212), we get a palindrome (41211011214).

The spelling of 21201001002 in words is "twenty-one billion, two hundred one million, one thousand, two".