3216405 has 16 divisors (see below), whose sum is σ = 5313024. Its totient is φ = 1659840.

The previous prime is 3216403. The next prime is 3216407. The reversal of 3216405 is 5046123.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (3216403) and next prime (3216407).

It is not a de Polignac number, because 3216405 - 2¹ = 3216403 is a prime.

It is a super-2 number, since 2×3216405² = 20690522248050, which contains 22 as substring.

3216405 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3216403) 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, 2994 + ... + 3923.

It is an arithmetic number, because the mean of its divisors is an integer number (332064).

Almost surely, 2^3216405 is an apocalyptic number.

It is an amenable number.

3216405 is a deficient number, since it is larger than the sum of its proper divisors (2096619).

3216405 is a wasteful number, since it uses less digits than its factorization.

3216405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6956.

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 3216405 is about 1793.4338571578. The cubic root of 3216405 is about 147.6126497483.

The spelling of 3216405 in words is "three million, two hundred sixteen thousand, four hundred five".