16216621 has 4 divisors (see below), whose sum is σ = 16340544. Its totient is φ = 16092700.

The previous prime is 16216609. The next prime is 16216631. The reversal of 16216621 is 12661261.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 16216621 - 2⁷ = 16216493 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 (16216631) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 61765 + ... + 62026.

It is an arithmetic number, because the mean of its divisors is an integer number (4085136).

Almost surely, 2^16216621 is an apocalyptic number.

It is an amenable number.

16216621 is a deficient number, since it is larger than the sum of its proper divisors (123923).

16216621 is a wasteful number, since it uses less digits than its factorization.

16216621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123922.

The product of its digits is 864, while the sum is 25.

The square root of 16216621 is about 4026.9865904917. The cubic root of 16216621 is about 253.1163051629.

Adding to 16216621 its reverse (12661261), we get a palindrome (28877882).

The spelling of 16216621 in words is "sixteen million, two hundred sixteen thousand, six hundred twenty-one".