1866491645 has 16 divisors (see below), whose sum is σ = 2255040000. Its totient is φ = 1483054848.

The previous prime is 1866491621. The next prime is 1866491663. The reversal of 1866491645 is 5461946681.

It is a cyclic number.

It is not a de Polignac number, because 1866491645 - 2¹⁰ = 1866490621 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1866491593 and 1866491602.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 714101 + ... + 716709.

It is an arithmetic number, because the mean of its divisors is an integer number (140940000).

Almost surely, 2^1866491645 is an apocalyptic number.

It is an amenable number.

1866491645 is a deficient number, since it is larger than the sum of its proper divisors (388548355).

1866491645 is a wasteful number, since it uses less digits than its factorization.

1866491645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3532.

The product of its digits is 1244160, while the sum is 50.

The square root of 1866491645 is about 43202.9124596942. The cubic root of 1866491645 is about 1231.2380169413.

The spelling of 1866491645 in words is "one billion, eight hundred sixty-six million, four hundred ninety-one thousand, six hundred forty-five".