642763221 has 16 divisors (see below), whose sum is σ = 925119360. Its totient is φ = 395743040.

The previous prime is 642763201. The next prime is 642763229. The reversal of 642763221 is 122367246.

It is a cyclic number.

It is not a de Polignac number, because 642763221 - 2⁵ = 642763189 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642763229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 158610 + ... + 162611.

It is an arithmetic number, because the mean of its divisors is an integer number (57819960).

Almost surely, 2^642763221 is an apocalyptic number.

It is an amenable number.

642763221 is a deficient number, since it is larger than the sum of its proper divisors (282356139).

642763221 is a wasteful number, since it uses less digits than its factorization.

642763221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 321276.

The product of its digits is 24192, while the sum is 33.

The square root of 642763221 is about 25352.7754101992. The cubic root of 642763221 is about 863.0123410103.

The spelling of 642763221 in words is "six hundred forty-two million, seven hundred sixty-three thousand, two hundred twenty-one".