21100002 has 64 divisors (see below), whose sum is σ = 53222400. Its totient is φ = 5417280.

The previous prime is 21099977. The next prime is 21100003. The reversal of 21100002 is 20000112.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (6).

It is not an unprimeable number, because it can be changed into a prime (21100003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 50149 + ... + 50567.

It is an arithmetic number, because the mean of its divisors is an integer number (831600).

Almost surely, 2^21100002 is an apocalyptic number.

21100002 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 21100002, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26611200).

21100002 is an abundant number, since it is smaller than the sum of its proper divisors (32122398).

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

21100002 is a wasteful number, since it uses less digits than its factorization.

21100002 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 551.

The product of its (nonzero) digits is 4, while the sum is 6.

The square root of 21100002 is about 4593.4738488425. The cubic root of 21100002 is about 276.3296575563.

Adding to 21100002 its reverse (20000112), we get a palindrome (41100114).

The spelling of 21100002 in words is "twenty-one million, one hundred thousand, two".