16775621 has 4 divisors (see below), whose sum is σ = 16851072. Its totient is φ = 16700172.

The previous prime is 16775609. The next prime is 16775639. The reversal of 16775621 is 12657761.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12657761 = 191 ⋅66271.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16775621 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 (16775221) 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, 37391 + ... + 37836.

It is an arithmetic number, because the mean of its divisors is an integer number (4212768).

Almost surely, 2^16775621 is an apocalyptic number.

It is an amenable number.

16775621 is a deficient number, since it is larger than the sum of its proper divisors (75451).

16775621 is an equidigital number, since it uses as much as digits as its factorization.

16775621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75450.

The product of its digits is 17640, while the sum is 35.

The square root of 16775621 is about 4095.8052932238. The cubic root of 16775621 is about 255.9918871534.

The spelling of 16775621 in words is "sixteen million, seven hundred seventy-five thousand, six hundred twenty-one".