40006638 has 72 divisors (see below), whose sum is σ = 102489192. Its totient is φ = 11243232.

The previous prime is 40006621. The next prime is 40006663. The reversal of 40006638 is 83660004.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 58756 + ... + 59432.

It is an arithmetic number, because the mean of its divisors is an integer number (1423461).

Almost surely, 2^40006638 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 40006638, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (51244596).

40006638 is an abundant number, since it is smaller than the sum of its proper divisors (62482554).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

40006638 is a wasteful number, since it uses less digits than its factorization.

40006638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 766 (or 756 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The square root of 40006638 is about 6325.0800785445. The cubic root of 40006638 is about 342.0141063228.

The spelling of 40006638 in words is "forty million, six thousand, six hundred thirty-eight".