21355120 has 40 divisors (see below), whose sum is σ = 49970016. Its totient is φ = 8487168.

The previous prime is 21355097. The next prime is 21355121. The reversal of 21355120 is 2155312.

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21355121) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13069 + ... + 14611.

Almost surely, 2^21355120 is an apocalyptic number.

21355120 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 21355120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24985008).

21355120 is an abundant number, since it is smaller than the sum of its proper divisors (28614896).

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

21355120 is a wasteful number, since it uses less digits than its factorization.

21355120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1729 (or 1723 counting only the distinct ones).

The product of its (nonzero) digits is 300, while the sum is 19.

The square root of 21355120 is about 4621.1600275256. The cubic root of 21355120 is about 277.4388903123.

The spelling of 21355120 in words is "twenty-one million, three hundred fifty-five thousand, one hundred twenty".