16638372 has 60 divisors (see below), whose sum is σ = 44060940. Its totient is φ = 5474304.

The previous prime is 16638371. The next prime is 16638403. The reversal of 16638372 is 27383661.

It is a happy number.

16638372 is a `hidden beast` number, since 16 + 638 + 3 + 7 + 2 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 11329956 + 5308416 = 3366^2 + 2304^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (16638371) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 28548 + ... + 29124.

It is an arithmetic number, because the mean of its divisors is an integer number (734349).

Almost surely, 2^16638372 is an apocalyptic number.

16638372 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 16638372, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22030470).

16638372 is an abundant number, since it is smaller than the sum of its proper divisors (27422568).

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

16638372 is a wasteful number, since it uses less digits than its factorization.

16638372 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 682 (or 671 counting only the distinct ones).

The product of its digits is 36288, while the sum is 36.

The square root of 16638372 is about 4079.0160578257. The cubic root of 16638372 is about 255.2918457878.

The spelling of 16638372 in words is "sixteen million, six hundred thirty-eight thousand, three hundred seventy-two".