16540221 has 8 divisors (see below), whose sum is σ = 22649824. Its totient is φ = 10728720.

The previous prime is 16540217. The next prime is 16540229. The reversal of 16540221 is 12204561.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 16540221 - 2² = 16540217 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16540229) 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, 74395 + ... + 74616.

It is an arithmetic number, because the mean of its divisors is an integer number (2831228).

Almost surely, 2^16540221 is an apocalyptic number.

It is an amenable number.

16540221 is a deficient number, since it is larger than the sum of its proper divisors (6109603).

16540221 is a wasteful number, since it uses less digits than its factorization.

16540221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149051.

The product of its (nonzero) digits is 480, while the sum is 21.

The square root of 16540221 is about 4066.9670517475. The cubic root of 16540221 is about 254.7888602112.

Adding to 16540221 its reverse (12204561), we get a palindrome (28744782).

It can be divided in two parts, 16540 and 221, that added together give a palindrome (16761).

The spelling of 16540221 in words is "sixteen million, five hundred forty thousand, two hundred twenty-one".