53665638 has 64 divisors (see below), whose sum is σ = 120318912. Its totient is φ = 15851520.

The previous prime is 53665637. The next prime is 53665649. The reversal of 53665638 is 83656635.

It is a self number, because there is not a number n which added to its sum of digits gives 53665638.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (53665637) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 310120 + ... + 310292.

It is an arithmetic number, because the mean of its divisors is an integer number (1879983).

Almost surely, 2^53665638 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 53665638, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (60159456).

53665638 is an abundant number, since it is smaller than the sum of its proper divisors (66653274).

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

53665638 is a wasteful number, since it uses less digits than its factorization.

53665638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 329.

The product of its digits is 388800, while the sum is 42.

The square root of 53665638 is about 7325.6834493445. The cubic root of 53665638 is about 377.1945701341.

The spelling of 53665638 in words is "fifty-three million, six hundred sixty-five thousand, six hundred thirty-eight".