21854380 has 48 divisors (see below), whose sum is σ = 47980800. Its totient is φ = 8352000.

The previous prime is 21854369. The next prime is 21854419. The reversal of 21854380 is 8345812.

It is a super-2 number, since 2×21854380² = 955227850368800, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a congruent number.

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, 62446 + ... + 62794.

It is an arithmetic number, because the mean of its divisors is an integer number (999600).

Almost surely, 2^21854380 is an apocalyptic number.

21854380 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 21854380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23990400).

21854380 is an abundant number, since it is smaller than the sum of its proper divisors (26126420).

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

21854380 is a wasteful number, since it uses less digits than its factorization.

21854380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 490 (or 488 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 31.

The square root of 21854380 is about 4674.8668430234. The cubic root of 21854380 is about 279.5843322146.

The spelling of 21854380 in words is "twenty-one million, eight hundred fifty-four thousand, three hundred eighty".