40639621 has 4 divisors (see below), whose sum is σ = 44334144. Its totient is φ = 36945100.

The previous prime is 40639609. The next prime is 40639637. The reversal of 40639621 is 12693604.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-40639621 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a pancake number, because a pancake can be divided into 40639621 parts by 9015 straight cuts.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40639691) 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, 1847245 + ... + 1847266.

It is an arithmetic number, because the mean of its divisors is an integer number (11083536).

Almost surely, 2^40639621 is an apocalyptic number.

It is an amenable number.

40639621 is a deficient number, since it is larger than the sum of its proper divisors (3694523).

40639621 is a wasteful number, since it uses less digits than its factorization.

40639621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3694522.

The product of its (nonzero) digits is 7776, while the sum is 31.

The square root of 40639621 is about 6374.9212544156. The cubic root of 40639621 is about 343.8084526054.

The spelling of 40639621 in words is "forty million, six hundred thirty-nine thousand, six hundred twenty-one".