42138189621 has 36 divisors (see below), whose sum is σ = 66935226540. Its totient is φ = 25525843200.

The previous prime is 42138189617. The next prime is 42138189637. The reversal of 42138189621 is 12698183124.

42138189621 is a `hidden beast` number, since 4 + 2 + 1 + 3 + 8 + 18 + 9 + 621 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 33447288996 + 8690900625 = 182886^2 + 93225^2 .

It is not a de Polignac number, because 42138189621 - 2² = 42138189617 is a prime.

42138189621 is a modest number, since divided by 189621 gives 42138 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42138189661) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 2541085 + ... + 2557613.

Almost surely, 2^42138189621 is an apocalyptic number.

It is an amenable number.

42138189621 is a deficient number, since it is larger than the sum of its proper divisors (24797036919).

42138189621 is a wasteful number, since it uses less digits than its factorization.

42138189621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18898 (or 18884 counting only the distinct ones).

The product of its digits is 165888, while the sum is 45.

The spelling of 42138189621 in words is "forty-two billion, one hundred thirty-eight million, one hundred eighty-nine thousand, six hundred twenty-one".