405166221 has 24 divisors (see below), whose sum is σ = 606579480. Its totient is φ = 260297856.

The previous prime is 405166213. The next prime is 405166277. The reversal of 405166221 is 122661504.

It can be written as a sum of positive squares in 4 ways, for example, as 148718025 + 256448196 = 12195^2 + 16014^2 .

It is not a de Polignac number, because 405166221 - 2³ = 405166213 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (405166721) 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, 175551 + ... + 177843.

It is an arithmetic number, because the mean of its divisors is an integer number (25274145).

Almost surely, 2^405166221 is an apocalyptic number.

It is an amenable number.

405166221 is a deficient number, since it is larger than the sum of its proper divisors (201413259).

405166221 is a wasteful number, since it uses less digits than its factorization.

405166221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3005 (or 3002 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The square root of 405166221 is about 20128.7411677929. The cubic root of 405166221 is about 739.9648272788.

The spelling of 405166221 in words is "four hundred five million, one hundred sixty-six thousand, two hundred twenty-one".