21540550 has 12 divisors (see below), whose sum is σ = 40065516. Its totient is φ = 8616200.

The previous prime is 21540529. The next prime is 21540551. The reversal of 21540550 is 5504512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21540551) 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, 215356 + ... + 215455.

It is an arithmetic number, because the mean of its divisors is an integer number (3338793).

Almost surely, 2^21540550 is an apocalyptic number.

21540550 is a deficient number, since it is larger than the sum of its proper divisors (18524966).

21540550 is a wasteful number, since it uses less digits than its factorization.

21540550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 430823 (or 430818 counting only the distinct ones).

The product of its (nonzero) digits is 1000, while the sum is 22.

The square root of 21540550 is about 4641.1798069026. The cubic root of 21540550 is about 278.2395929759.

The spelling of 21540550 in words is "twenty-one million, five hundred forty thousand, five hundred fifty".