16221401 has 24 divisors (see below), whose sum is σ = 19918080. Its totient is φ = 13154400.

The previous prime is 16221391. The next prime is 16221431. The reversal of 16221401 is 10412261.

It is not a de Polignac number, because 16221401 - 2¹⁸ = 15959257 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 16221401.

It is not an unprimeable number, because it can be changed into a prime (16221431) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 89531 + ... + 89711.

It is an arithmetic number, because the mean of its divisors is an integer number (829920).

Almost surely, 2^16221401 is an apocalyptic number.

It is an amenable number.

16221401 is a deficient number, since it is larger than the sum of its proper divisors (3696679).

16221401 is a wasteful number, since it uses less digits than its factorization.

16221401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 285 (or 278 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 17.

The square root of 16221401 is about 4027.5800426559. The cubic root of 16221401 is about 253.1411721822.

Adding to 16221401 its reverse (10412261), we get a palindrome (26633662).

The spelling of 16221401 in words is "sixteen million, two hundred twenty-one thousand, four hundred one".