21378100 has 36 divisors (see below), whose sum is σ = 47059488. Its totient is φ = 8428000.

The previous prime is 21378083. The next prime is 21378107. The reversal of 21378100 is 187312.

It is a super-2 number, since 2×21378100² = 914046319220000, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21378107) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5595 + ... + 8605.

It is an arithmetic number, because the mean of its divisors is an integer number (1307208).

Almost surely, 2^21378100 is an apocalyptic number.

21378100 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 21378100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23529744).

21378100 is an abundant number, since it is smaller than the sum of its proper divisors (25681388).

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

21378100 is a wasteful number, since it uses less digits than its factorization.

21378100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3096 (or 3089 counting only the distinct ones).

The product of its (nonzero) digits is 336, while the sum is 22.

The square root of 21378100 is about 4623.6457476757. The cubic root of 21378100 is about 277.5383709081.

The spelling of 21378100 in words is "twenty-one million, three hundred seventy-eight thousand, one hundred".