40639638 has 16 divisors (see below), whose sum is σ = 87531696. Its totient is φ = 12504480.

The previous prime is 40639637. The next prime is 40639691. The reversal of 40639638 is 83693604.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a junction number, because it is equal to n+sod(n) for n = 40639596 and 40639605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40639637) 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, 260433 + ... + 260588.

It is an arithmetic number, because the mean of its divisors is an integer number (5470731).

Almost surely, 2^40639638 is an apocalyptic number.

40639638 is an abundant number, since it is smaller than the sum of its proper divisors (46892058).

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

40639638 is a wasteful number, since it uses less digits than its factorization.

40639638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 521039.

The product of its (nonzero) digits is 93312, while the sum is 39.

The square root of 40639638 is about 6374.9225877653. The cubic root of 40639638 is about 343.8085005450.

The spelling of 40639638 in words is "forty million, six hundred thirty-nine thousand, six hundred thirty-eight".