15964221 has 16 divisors (see below), whose sum is σ = 26198144. Its totient is φ = 8420544.

The previous prime is 15964219. The next prime is 15964253. The reversal of 15964221 is 12246951.

It is not a de Polignac number, because 15964221 - 2¹ = 15964219 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15964261) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28966 + ... + 29511.

It is an arithmetic number, because the mean of its divisors is an integer number (1637384).

Almost surely, 2^15964221 is an apocalyptic number.

It is an amenable number.

15964221 is a deficient number, since it is larger than the sum of its proper divisors (10233923).

15964221 is a wasteful number, since it uses less digits than its factorization.

15964221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58500.

The product of its digits is 4320, while the sum is 30.

The square root of 15964221 is about 3995.5251219333. The cubic root of 15964221 is about 251.7962418184.

The spelling of 15964221 in words is "fifteen million, nine hundred sixty-four thousand, two hundred twenty-one".