402564221 has 4 divisors (see below), whose sum is σ = 403228032. Its totient is φ = 401900412.

The previous prime is 402564187. The next prime is 402564251. The reversal of 402564221 is 122465204.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 402564221 - 2¹⁴ = 402547837 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (402564251) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 330995 + ... + 332208.

It is an arithmetic number, because the mean of its divisors is an integer number (100807008).

Almost surely, 2^402564221 is an apocalyptic number.

It is an amenable number.

402564221 is a deficient number, since it is larger than the sum of its proper divisors (663811).

402564221 is an equidigital number, since it uses as much as digits as its factorization.

402564221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 663810.

The product of its (nonzero) digits is 3840, while the sum is 26.

The square root of 402564221 is about 20064.0031150317. The cubic root of 402564221 is about 738.3773924601.

The spelling of 402564221 in words is "four hundred two million, five hundred sixty-four thousand, two hundred twenty-one".