21000421002 has 64 divisors (see below), whose sum is σ = 47092929408. Its totient is φ = 6187104000.

The previous prime is 21000420983. The next prime is 21000421003. The reversal of 21000421002 is 20012400012.

It is a super-2 number, since 2×21000421002² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21000421003) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4542252 + ... + 4546872.

It is an arithmetic number, because the mean of its divisors is an integer number (735827022).

Almost surely, 2^21000421002 is an apocalyptic number.

21000421002 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 21000421002, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23546464704).

21000421002 is an abundant number, since it is smaller than the sum of its proper divisors (26092508406).

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

21000421002 is a wasteful number, since it uses less digits than its factorization.

21000421002 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6535.

The product of its (nonzero) digits is 32, while the sum is 12.

Adding to 21000421002 its reverse (20012400012), we get a palindrome (41012821014).

The spelling of 21000421002 in words is "twenty-one billion, four hundred twenty-one thousand, two".