16221405 has 16 divisors (see below), whose sum is σ = 26006400. Its totient is φ = 8634048.

The previous prime is 16221391. The next prime is 16221431. The reversal of 16221405 is 50412261.

It is not a de Polignac number, because 16221405 - 2⁴ = 16221389 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10896 + ... + 12294.

It is an arithmetic number, because the mean of its divisors is an integer number (1625400).

Almost surely, 2^16221405 is an apocalyptic number.

16221405 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

16221405 is a deficient number, since it is larger than the sum of its proper divisors (9784995).

16221405 is a wasteful number, since it uses less digits than its factorization.

16221405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2180.

The product of its (nonzero) digits is 480, while the sum is 21.

The square root of 16221405 is about 4027.5805392320. The cubic root of 16221405 is about 253.1411929894.

Adding to 16221405 its reverse (50412261), we get a palindrome (66633666).

The spelling of 16221405 in words is "sixteen million, two hundred twenty-one thousand, four hundred five".