21001001002 has 16 divisors (see below), whose sum is σ = 31670369280. Its totient is φ = 10444241808.

The previous prime is 21001000991. The next prime is 21001001009. The reversal of 21001001002 is 20010010012.

It is not an unprimeable number, because it can be changed into a prime (21001001009) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2220199 + ... + 2229637.

It is an arithmetic number, because the mean of its divisors is an integer number (1979398080).

Almost surely, 2^21001001002 is an apocalyptic number.

21001001002 is a deficient number, since it is larger than the sum of its proper divisors (10669368278).

21001001002 is a wasteful number, since it uses less digits than its factorization.

21001001002 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15285.

The product of its (nonzero) digits is 4, while the sum is 7.

Adding to 21001001002 its reverse (20010010012), we get a palindrome (41011011014).

The spelling of 21001001002 in words is "twenty-one billion, one million, one thousand, two".