21002201100 has 72 divisors (see below), whose sum is σ = 67518195920. Its totient is φ = 5600586240.

The previous prime is 21002201069. The next prime is 21002201123. The reversal of 21002201100 is 110220012.

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 23 ways as a sum of consecutive naturals, for example, 3886597 + ... + 3891996.

Almost surely, 2^21002201100 is an apocalyptic number.

21002201100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21002201100 is an abundant number, since it is smaller than the sum of its proper divisors (46515994820).

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

21002201100 is a wasteful number, since it uses less digits than its factorization.

21002201100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7778616 (or 7778603 counting only the distinct ones).

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

Adding to 21002201100 its reverse (110220012), we get a palindrome (21112421112).

The spelling of 21002201100 in words is "twenty-one billion, two million, two hundred one thousand, one hundred".