16545621 has 4 divisors (see below), whose sum is σ = 22060832. Its totient is φ = 11030412.

The previous prime is 16545619. The next prime is 16545629. The reversal of 16545621 is 12654561.

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 not a de Polignac number, because 16545621 - 2¹ = 16545619 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16545629) 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, 2757601 + ... + 2757606.

It is an arithmetic number, because the mean of its divisors is an integer number (5515208).

Almost surely, 2^16545621 is an apocalyptic number.

It is an amenable number.

16545621 is a deficient number, since it is larger than the sum of its proper divisors (5515211).

16545621 is an equidigital number, since it uses as much as digits as its factorization.

16545621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5515210.

The product of its digits is 7200, while the sum is 30.

The square root of 16545621 is about 4067.6308829588. The cubic root of 16545621 is about 254.8165847530.

The spelling of 16545621 in words is "sixteen million, five hundred forty-five thousand, six hundred twenty-one".