1821269866 has 16 divisors (see below), whose sum is σ = 2972385864. Its totient is φ = 831919104.

The previous prime is 1821269831. The next prime is 1821269869. The reversal of 1821269866 is 6689621281.

It can be written as a sum of positive squares in 4 ways, for example, as 1510488225 + 310781641 = 38865^2 + 17629^2 .

It is not an unprimeable number, because it can be changed into a prime (1821269869) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 358555 + ... + 363598.

Almost surely, 2^1821269866 is an apocalyptic number.

1821269866 is a deficient number, since it is larger than the sum of its proper divisors (1151115998).

1821269866 is a wasteful number, since it uses less digits than its factorization.

1821269866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 722265.

The product of its digits is 497664, while the sum is 49.

The square root of 1821269866 is about 42676.3384793026. The cubic root of 1821269866 is about 1221.2130427808.

The spelling of 1821269866 in words is "one billion, eight hundred twenty-one million, two hundred sixty-nine thousand, eight hundred sixty-six".