21853760 has 56 divisors (see below), whose sum is σ = 53742336. Its totient is φ = 8455680.

The previous prime is 21853757. The next prime is 21853763. The reversal of 21853760 is 6735812.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21853757) and next prime (21853763).

It is a super-2 number, since 2×21853760² = 955173652275200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is not an unprimeable number, because it can be changed into a prime (21853763) 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 7 ways as a sum of consecutive naturals, for example, 8819 + ... + 11021.

Almost surely, 2^21853760 is an apocalyptic number.

21853760 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 21853760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26871168).

21853760 is an abundant number, since it is smaller than the sum of its proper divisors (31888576).

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

21853760 is a wasteful number, since it uses less digits than its factorization.

21853760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2251 (or 2241 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 32.

The square root of 21853760 is about 4674.8005305039. The cubic root of 21853760 is about 279.5816882911.

The spelling of 21853760 in words is "twenty-one million, eight hundred fifty-three thousand, seven hundred sixty".