1866726769 has 4 divisors (see below), whose sum is σ = 1976534244. Its totient is φ = 1756919296.

The previous prime is 1866726767. The next prime is 1866726773. The reversal of 1866726769 is 9676276681.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9676276681 = 1723 ⋅5615947.

It can be written as a sum of positive squares in 2 ways, for example, as 1257624369 + 609102400 = 35463^2 + 24680^2 .

It is a cyclic number.

It is not a de Polignac number, because 1866726769 - 2¹ = 1866726767 is a prime.

It is a super-2 number, since 2×1866726769² = 6969337660202358722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1866726767) 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, 54903712 + ... + 54903745.

It is an arithmetic number, because the mean of its divisors is an integer number (494133561).

Almost surely, 2^1866726769 is an apocalyptic number.

It is an amenable number.

1866726769 is a deficient number, since it is larger than the sum of its proper divisors (109807475).

1866726769 is a wasteful number, since it uses less digits than its factorization.

1866726769 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109807474.

The product of its digits is 9144576, while the sum is 58.

The square root of 1866726769 is about 43205.6335331401. The cubic root of 1866726769 is about 1231.2897149051.

The spelling of 1866726769 in words is "one billion, eight hundred sixty-six million, seven hundred twenty-six thousand, seven hundred sixty-nine".