21603506100 has 144 divisors (see below), whose sum is σ = 68864717376. Its totient is φ = 5185280000.

The previous prime is 21603506087. The next prime is 21603506101. The reversal of 21603506100 is 160530612.

It is a super-2 number, since 2×21603506100² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21603506101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 300892 + ... + 365708.

It is an arithmetic number, because the mean of its divisors is an integer number (478227204).

Almost surely, 2^21603506100 is an apocalyptic number.

21603506100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21603506100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34432358688).

21603506100 is an abundant number, since it is smaller than the sum of its proper divisors (47261211276).

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

21603506100 is a wasteful number, since it uses less digits than its factorization.

21603506100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64946 (or 64939 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 24.

The spelling of 21603506100 in words is "twenty-one billion, six hundred three million, five hundred six thousand, one hundred".