3638681 has 4 divisors (see below), whose sum is σ = 3674112. Its totient is φ = 3603252.

The previous prime is 3638653. The next prime is 3638699. The reversal of 3638681 is 1868363.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1868363 = 7 ⋅266909.

It is a cyclic number.

It is not a de Polignac number, because 3638681 - 2¹⁸ = 3376537 is a prime.

It is a super-2 number, since 2×3638681² = 26479998839522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3638641) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17561 + ... + 17766.

It is an arithmetic number, because the mean of its divisors is an integer number (918528).

Almost surely, 2^3638681 is an apocalyptic number.

It is an amenable number.

3638681 is a deficient number, since it is larger than the sum of its proper divisors (35431).

3638681 is a wasteful number, since it uses less digits than its factorization.

3638681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35430.

The product of its digits is 20736, while the sum is 35.

The square root of 3638681 is about 1907.5326995887. The cubic root of 3638681 is about 153.8088509367.

The spelling of 3638681 in words is "three million, six hundred thirty-eight thousand, six hundred eighty-one".