3638421681 has 8 divisors (see below), whose sum is σ = 5062152000. Its totient is φ = 2320152912.

The previous prime is 3638421659. The next prime is 3638421691. The reversal of 3638421681 is 1861248363.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 3638421681 - 2¹¹ = 3638419633 is a prime.

It is a super-2 number, since 2×3638421681² = 26476224657541731522, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (3638421601) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26365306 + ... + 26365443.

It is an arithmetic number, because the mean of its divisors is an integer number (632769000).

Almost surely, 2^3638421681 is an apocalyptic number.

It is an amenable number.

3638421681 is a deficient number, since it is larger than the sum of its proper divisors (1423730319).

3638421681 is a wasteful number, since it uses less digits than its factorization.

3638421681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52730775.

The product of its digits is 165888, while the sum is 42.

The square root of 3638421681 is about 60319.3309064350. The cubic root of 3638421681 is about 1538.0519700231.

The spelling of 3638421681 in words is "three billion, six hundred thirty-eight million, four hundred twenty-one thousand, six hundred eighty-one".