21849520 has 80 divisors (see below), whose sum is σ = 63353088. Its totient is φ = 6808320.

The previous prime is 21849511. The next prime is 21849521. The reversal of 21849520 is 2594812.

It is a tau number, because it is divible by the number of its divisors (80).

It is not an unprimeable number, because it can be changed into a prime (21849521) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4387 + ... + 7933.

Almost surely, 2^21849520 is an apocalyptic number.

21849520 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 21849520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31676544).

21849520 is an abundant number, since it is smaller than the sum of its proper divisors (41503568).

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

21849520 is a wasteful number, since it uses less digits than its factorization.

21849520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3578 (or 3572 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 31.

The square root of 21849520 is about 4674.3470132201. The cubic root of 21849520 is about 279.5636059255.

The spelling of 21849520 in words is "twenty-one million, eight hundred forty-nine thousand, five hundred twenty".