1866564656 has 20 divisors (see below), whose sum is σ = 3945239304. Its totient is φ = 848438400.

The previous prime is 1866564629. The next prime is 1866564719. The reversal of 1866564656 is 6564656681.

It is a junction number, because it is equal to n+sod(n) for n = 1866564598 and 1866564607.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5302565 + ... + 5302916.

Almost surely, 2^1866564656 is an apocalyptic number.

1866564656 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1866564656 is an abundant number, since it is smaller than the sum of its proper divisors (2078674648).

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

1866564656 is a wasteful number, since it uses less digits than its factorization.

1866564656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10605500 (or 10605494 counting only the distinct ones).

The product of its digits is 6220800, while the sum is 53.

The square root of 1866564656 is about 43203.7574291866. The cubic root of 1866564656 is about 1231.2540707227.

The spelling of 1866564656 in words is "one billion, eight hundred sixty-six million, five hundred sixty-four thousand, six hundred fifty-six".