36666781 has 4 divisors (see below), whose sum is σ = 36679932. Its totient is φ = 36653632.

The previous prime is 36666757. The next prime is 36666797. The reversal of 36666781 is 18766663.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 18766663 = 127 ⋅147769.

It can be written as a sum of positive squares in 2 ways, for example, as 12744900 + 23921881 = 3570^2 + 4891^2 .

It is a cyclic number.

It is not a de Polignac number, because 36666781 - 2²¹ = 34569629 is a prime.

It is a super-2 number, since 2×36666781² = 2688905657803922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (36666731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 556 + ... + 8581.

It is an arithmetic number, because the mean of its divisors is an integer number (9169983).

Almost surely, 2^36666781 is an apocalyptic number.

It is an amenable number.

36666781 is a deficient number, since it is larger than the sum of its proper divisors (13151).

36666781 is an equidigital number, since it uses as much as digits as its factorization.

36666781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13150.

The product of its digits is 217728, while the sum is 43.

The square root of 36666781 is about 6055.3101489519. The cubic root of 36666781 is about 332.2188431097.

The spelling of 36666781 in words is "thirty-six million, six hundred sixty-six thousand, seven hundred eighty-one".