642181122 has 90 divisors (see below), whose sum is σ = 1590455097. Its totient is φ = 193525200.

The previous prime is 642181117. The next prime is 642181153. The reversal of 642181122 is 221181246.

642181122 is a `hidden beast` number, since 642 + 1 + 8 + 1 + 12 + 2 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 388129401 + 254051721 = 19701^2 + 15939^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=17919.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 3547872 + ... + 3548052.

Almost surely, 2^642181122 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 642181122

642181122 is an abundant number, since it is smaller than the sum of its proper divisors (948273975).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

642181122 is a wasteful number, since it uses less digits than its factorization.

642181122 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 398 (or 197 counting only the distinct ones).

The product of its digits is 1536, while the sum is 27.

The square root of 642181122 is about 25341.2928241635. The cubic root of 642181122 is about 862.7517420166.

The spelling of 642181122 in words is "six hundred forty-two million, one hundred eighty-one thousand, one hundred twenty-two".