21378000 has 160 divisors (see below), whose sum is σ = 78923520. Its totient is φ = 4876800.

The previous prime is 21377981. The next prime is 21378011. The reversal of 21378000 is 87312.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 41746 + ... + 42254.

It is an arithmetic number, because the mean of its divisors is an integer number (493272).

Almost surely, 2^21378000 is an apocalyptic number.

21378000 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 21378000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39461760).

21378000 is an abundant number, since it is smaller than the sum of its proper divisors (57545520).

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

21378000 is a wasteful number, since it uses less digits than its factorization.

21378000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 542 (or 526 counting only the distinct ones).

The product of its (nonzero) digits is 336, while the sum is 21.

The square root of 21378000 is about 4623.6349336858. The cubic root of 21378000 is about 277.5379381618.

The spelling of 21378000 in words is "twenty-one million, three hundred seventy-eight thousand".