21378852 has 36 divisors (see below), whose sum is σ = 58954896. Its totient is φ = 6478320.

The previous prime is 21378817. The next prime is 21378883. The reversal of 21378852 is 25887312.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

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 11 ways as a sum of consecutive naturals, for example, 26598 + ... + 27389.

It is an arithmetic number, because the mean of its divisors is an integer number (1637636).

Almost surely, 2^21378852 is an apocalyptic number.

21378852 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21378852 is an abundant number, since it is smaller than the sum of its proper divisors (37576044).

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

21378852 is a wasteful number, since it uses less digits than its factorization.

21378852 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54008 (or 54003 counting only the distinct ones).

The product of its digits is 26880, while the sum is 36.

The square root of 21378852 is about 4623.7270680697. The cubic root of 21378852 is about 277.5416251170.

It can be divided in two parts, 21 and 378852, that added together give a palindrome (378873).

The spelling of 21378852 in words is "twenty-one million, three hundred seventy-eight thousand, eight hundred fifty-two".