1866211989 has 16 divisors (see below), whose sum is σ = 2517645312. Its totient is φ = 1229510448.

The previous prime is 1866211987. The next prime is 1866211993. The reversal of 1866211989 is 9891126681.

1866211989 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 1866211989 - 2¹ = 1866211987 is a prime.

It is a super-2 number, since 2×1866211989² = 6965494375774672242, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1866211987) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 149424 + ... + 161430.

It is an arithmetic number, because the mean of its divisors is an integer number (157352832).

Almost surely, 2^1866211989 is an apocalyptic number.

It is an amenable number.

1866211989 is a deficient number, since it is larger than the sum of its proper divisors (651433323).

1866211989 is a wasteful number, since it uses less digits than its factorization.

1866211989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12616.

The product of its digits is 373248, while the sum is 51.

The square root of 1866211989 is about 43199.6757973946. The cubic root of 1866211989 is about 1231.1765218367.

The spelling of 1866211989 in words is "one billion, eight hundred sixty-six million, two hundred eleven thousand, nine hundred eighty-nine".