21355000 has 40 divisors (see below), whose sum is σ = 50046480. Its totient is φ = 8540000.

The previous prime is 21354989. The next prime is 21355003. The reversal of 21355000 is 55312.

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 (21355003) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 2865 + ... + 7135.

It is an arithmetic number, because the mean of its divisors is an integer number (1251162).

Almost surely, 2^21355000 is an apocalyptic number.

21355000 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 21355000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25023240).

21355000 is an abundant number, since it is smaller than the sum of its proper divisors (28691480).

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

21355000 is an equidigital number, since it uses as much as digits as its factorization.

21355000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4297 (or 4278 counting only the distinct ones).

The product of its (nonzero) digits is 150, while the sum is 16.

The square root of 21355000 is about 4621.1470437544. The cubic root of 21355000 is about 277.4383706442.

The spelling of 21355000 in words is "twenty-one million, three hundred fifty-five thousand".