21354380 has 48 divisors (see below), whose sum is σ = 47882016. Its totient is φ = 7971840.

The previous prime is 21354349. The next prime is 21354391. The reversal of 21354380 is 8345312.

It is a super-3 number, since 3×21354380³ (a number of 23 digits) contains 333 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 61367 + ... + 61713.

It is an arithmetic number, because the mean of its divisors is an integer number (997542).

Almost surely, 2^21354380 is an apocalyptic number.

21354380 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 21354380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23941008).

21354380 is an abundant number, since it is smaller than the sum of its proper divisors (26527636).

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

21354380 is a wasteful number, since it uses less digits than its factorization.

21354380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 554 (or 552 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 26.

The square root of 21354380 is about 4621.0799603556. The cubic root of 21354380 is about 277.4356856609.

Adding to 21354380 its reverse (8345312), we get a palindrome (29699692).

The spelling of 21354380 in words is "twenty-one million, three hundred fifty-four thousand, three hundred eighty".