1866118729 has 4 divisors (see below), whose sum is σ = 1897747920. Its totient is φ = 1834489540.

The previous prime is 1866118693. The next prime is 1866118733. The reversal of 1866118729 is 9278116681.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 9278116681 = 641 ⋅14474441.

It is a cyclic number.

It is not a de Polignac number, because 1866118729 - 2⁹ = 1866118217 is a prime.

It is a super-2 number, since 2×1866118729² = 6964798221449150882, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1866118739) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15814507 + ... + 15814624.

It is an arithmetic number, because the mean of its divisors is an integer number (474436980).

Almost surely, 2^1866118729 is an apocalyptic number.

It is an amenable number.

1866118729 is a deficient number, since it is larger than the sum of its proper divisors (31629191).

1866118729 is an equidigital number, since it uses as much as digits as its factorization.

1866118729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31629190.

The product of its digits is 290304, while the sum is 49.

The square root of 1866118729 is about 43198.5963776602. The cubic root of 1866118729 is about 1231.1560130135.

The spelling of 1866118729 in words is "one billion, eight hundred sixty-six million, one hundred eighteen thousand, seven hundred twenty-nine".