21378700 has 54 divisors (see below), whose sum is σ = 53978316. Its totient is φ = 7328160.

The previous prime is 21378691. The next prime is 21378701. The reversal of 21378700 is 787312.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is not an unprimeable number, because it can be changed into a prime (21378701) by changing a digit.

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 17 ways as a sum of consecutive naturals, for example, 2719 + ... + 7081.

Almost surely, 2^21378700 is an apocalyptic number.

21378700 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 21378700, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26989158).

21378700 is an abundant number, since it is smaller than the sum of its proper divisors (32599616).

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

21378700 is a wasteful number, since it uses less digits than its factorization.

21378700 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4391 (or 4377 counting only the distinct ones).

The product of its (nonzero) digits is 2352, while the sum is 28.

The square root of 21378700 is about 4623.7106310841. The cubic root of 21378700 is about 277.5409673575.

The spelling of 21378700 in words is "twenty-one million, three hundred seventy-eight thousand, seven hundred".