40001639 has 4 divisors (see below), whose sum is σ = 40109256. Its totient is φ = 39894024.

The previous prime is 40001627. The next prime is 40001641. The reversal of 40001639 is 93610004.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-40001639 is a prime.

It is a super-2 number, since 2×40001639² = 3200262245372642, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40001939) 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 3 ways as a sum of consecutive naturals, for example, 53249 + ... + 53994.

It is an arithmetic number, because the mean of its divisors is an integer number (10027314).

Almost surely, 2^40001639 is an apocalyptic number.

40001639 is a deficient number, since it is larger than the sum of its proper divisors (107617).

40001639 is a wasteful number, since it uses less digits than its factorization.

40001639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107616.

The product of its (nonzero) digits is 648, while the sum is 23.

The square root of 40001639 is about 6324.6848933366. The cubic root of 40001639 is about 341.9998603558. Note that the first 3 decimals are identical.

The spelling of 40001639 in words is "forty million, one thousand, six hundred thirty-nine".