18861644 has 6 divisors (see below), whose sum is σ = 33007884. Its totient is φ = 9430820.

The previous prime is 18861643. The next prime is 18861673. The reversal of 18861644 is 44616881.

It is a super-2 number, since 2×18861644² = 711523228765472, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 18861598 and 18861607.

It is not an unprimeable number, because it can be changed into a prime (18861643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2357702 + ... + 2357709.

It is an arithmetic number, because the mean of its divisors is an integer number (5501314).

Almost surely, 2^18861644 is an apocalyptic number.

It is an amenable number.

18861644 is a deficient number, since it is larger than the sum of its proper divisors (14146240).

18861644 is a wasteful number, since it uses less digits than its factorization.

18861644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4715415 (or 4715413 counting only the distinct ones).

The product of its digits is 36864, while the sum is 38.

The square root of 18861644 is about 4342.9994243610. Note that the first 3 decimals coincide. The cubic root of 18861644 is about 266.1908856542.

The spelling of 18861644 in words is "eighteen million, eight hundred sixty-one thousand, six hundred forty-four".