402556221 has 12 divisors (see below), whose sum is σ = 601521180. Its totient is φ = 259116480.

The previous prime is 402556213. The next prime is 402556247. The reversal of 402556221 is 122655204.

It can be written as a sum of positive squares in 2 ways, for example, as 330730596 + 71825625 = 18186^2 + 8475^2 .

It is not a de Polignac number, because 402556221 - 2³ = 402556213 is a prime.

It is a super-2 number, since 2×402556221² = 324103022131601682, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (402556291) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 770920 + ... + 771441.

It is an arithmetic number, because the mean of its divisors is an integer number (50126765).

Almost surely, 2^402556221 is an apocalyptic number.

It is an amenable number.

402556221 is a deficient number, since it is larger than the sum of its proper divisors (198964959).

402556221 is a wasteful number, since it uses less digits than its factorization.

402556221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1542396 (or 1542393 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 27.

The square root of 402556221 is about 20063.8037520307. The cubic root of 402556221 is about 738.3725012668.

The spelling of 402556221 in words is "four hundred two million, five hundred fifty-six thousand, two hundred twenty-one".