21534550 has 12 divisors (see below), whose sum is σ = 40054356. Its totient is φ = 8613800.

The previous prime is 21534547. The next prime is 21534551. The reversal of 21534550 is 5543512.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21534551) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 215296 + ... + 215395.

It is an arithmetic number, because the mean of its divisors is an integer number (3337863).

Almost surely, 2^21534550 is an apocalyptic number.

21534550 is a deficient number, since it is larger than the sum of its proper divisors (18519806).

21534550 is a wasteful number, since it uses less digits than its factorization.

21534550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 430703 (or 430698 counting only the distinct ones).

The product of its (nonzero) digits is 3000, while the sum is 25.

The square root of 21534550 is about 4640.5333745163. The cubic root of 21534550 is about 278.2137565482.

The spelling of 21534550 in words is "twenty-one million, five hundred thirty-four thousand, five hundred fifty".