21326100 has 72 divisors (see below), whose sum is σ = 62683488. Its totient is φ = 5596800.

The previous prime is 21326099. The next prime is 21326101. The reversal of 21326100 is 162312.

It is an interprime number because it is at equal distance from previous prime (21326099) and next prime (21326101).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21326100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21326101) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 19570 + ... + 20630.

It is an arithmetic number, because the mean of its divisors is an integer number (870604).

Almost surely, 2^21326100 is an apocalyptic number.

21326100 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 21326100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31341744).

21326100 is an abundant number, since it is smaller than the sum of its proper divisors (41357388).

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

21326100 is a wasteful number, since it uses less digits than its factorization.

21326100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1145 (or 1138 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 15.

The square root of 21326100 is about 4618.0190558290. The cubic root of 21326100 is about 277.3131604893.

Adding to 21326100 its reverse (162312), we get a palindrome (21488412).

The spelling of 21326100 in words is "twenty-one million, three hundred twenty-six thousand, one hundred".