1236138642 has 18 divisors (see below), whose sum is σ = 2678623623. Its totient is φ = 411996492.

The previous prime is 1236138641. The next prime is 1236138649. The reversal of 1236138642 is 2468316321.

1236138642 is a `hidden beast` number, since 1 + 2 + 3 + 6 + 1 + 3 + 8 + 642 = 666.

It can be written as a sum of positive squares in only one way, i.e., 618069321 + 618069321 = 24861^2 + 24861^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=24861.

It is a junction number, because it is equal to n+sod(n) for n = 1236138597 and 1236138606.

It is not an unprimeable number, because it can be changed into a prime (1236138641) 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 8 ways as a sum of consecutive naturals, for example, 145023 + ... + 153309.

Almost surely, 2^1236138642 is an apocalyptic number.

1236138642 is an abundant number, since it is smaller than the sum of its proper divisors (1442484981).

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

1236138642 is an frugal number, since it uses more digits than its factorization.

1236138642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16582 (or 8292 counting only the distinct ones).

The product of its digits is 41472, while the sum is 36.

The square root of 1236138642 is about 35158.7633741575. The cubic root of 1236138642 is about 1073.2207501433.

Multiplying 1236138642 by its product of digits (41472), we get a square (51265141761024 = 7159968²).

The spelling of 1236138642 in words is "one billion, two hundred thirty-six million, one hundred thirty-eight thousand, six hundred forty-two".