42636681 has 6 divisors (see below), whose sum is σ = 61586330. Its totient is φ = 28424448.

The previous prime is 42636677. The next prime is 42636683. The reversal of 42636681 is 18663624.

It can be written as a sum of positive squares in only one way, i.e., 22467600 + 20169081 = 4740^2 + 4491^2 .

It is not a de Polignac number, because 42636681 - 2² = 42636677 is a prime.

It is a super-2 number, since 2×42636681² = 3635773133391522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (42636683) by changing a digit.

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 5 ways as a sum of consecutive naturals, for example, 2368696 + ... + 2368713.

Almost surely, 2^42636681 is an apocalyptic number.

It is an amenable number.

42636681 is a deficient number, since it is larger than the sum of its proper divisors (18949649).

42636681 is a wasteful number, since it uses less digits than its factorization.

42636681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4737415 (or 4737412 counting only the distinct ones).

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

The square root of 42636681 is about 6529.6769445356. The cubic root of 42636681 is about 349.3503076710.

The spelling of 42636681 in words is "forty-two million, six hundred thirty-six thousand, six hundred eighty-one".