7666638 has 48 divisors (see below), whose sum is σ = 18098640. Its totient is φ = 2158464.

The previous prime is 7666621. The next prime is 7666639. The reversal of 7666638 is 8366667.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 7666638.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7666639) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 26020 + ... + 26312.

It is an arithmetic number, because the mean of its divisors is an integer number (377055).

Almost surely, 2^7666638 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 7666638, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (9049320).

7666638 is an abundant number, since it is smaller than the sum of its proper divisors (10432002).

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

7666638 is a wasteful number, since it uses less digits than its factorization.

7666638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 401 (or 394 counting only the distinct ones).

The product of its digits is 217728, while the sum is 42.

The square root of 7666638 is about 2768.8694443762. The cubic root of 7666638 is about 197.1824775591.

The spelling of 7666638 in words is "seven million, six hundred sixty-six thousand, six hundred thirty-eight".