18661356 has 108 divisors (see below), whose sum is σ = 56019600. Its totient is φ = 5221440.

The previous prime is 18661339. The next prime is 18661369. The reversal of 18661356 is 65316681.

It is a happy number.

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

It is a self number, because there is not a number n which added to its sum of digits gives 18661356.

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, 125170 + ... + 125318.

It is an arithmetic number, because the mean of its divisors is an integer number (518700).

Almost surely, 2^18661356 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18661356, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28009800).

18661356 is an abundant number, since it is smaller than the sum of its proper divisors (37358244).

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

18661356 is a wasteful number, since it uses less digits than its factorization.

18661356 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 244 (or 232 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

The square root of 18661356 is about 4319.8791649767. The cubic root of 18661356 is about 265.2453216565.

The spelling of 18661356 in words is "eighteen million, six hundred sixty-one thousand, three hundred fifty-six".