16901221 has 4 divisors (see below), whose sum is σ = 16987212. Its totient is φ = 16815232.

The previous prime is 16901201. The next prime is 16901233. The reversal of 16901221 is 12210961.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12210961 = 7 ⋅1744423.

It can be written as a sum of positive squares in 2 ways, for example, as 16524225 + 376996 = 4065^2 + 614^2 .

It is a cyclic number.

It is not a de Polignac number, because 16901221 - 2¹³ = 16893029 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 16901192 and 16901201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16901201) 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, 42700 + ... + 43093.

It is an arithmetic number, because the mean of its divisors is an integer number (4246803).

Almost surely, 2^16901221 is an apocalyptic number.

It is an amenable number.

16901221 is a deficient number, since it is larger than the sum of its proper divisors (85991).

16901221 is an equidigital number, since it uses as much as digits as its factorization.

16901221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85990.

The product of its (nonzero) digits is 216, while the sum is 22.

The square root of 16901221 is about 4111.1094609606. The cubic root of 16901221 is about 256.6291744491.

The spelling of 16901221 in words is "sixteen million, nine hundred one thousand, two hundred twenty-one".