3687781 has 4 divisors (see below), whose sum is σ = 3716064. Its totient is φ = 3659500.

The previous prime is 3687769. The next prime is 3687787. The reversal of 3687781 is 1877863.

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: 1877863 = 13 ⋅144451.

It is a cyclic number.

It is not a de Polignac number, because 3687781 - 2¹⁹ = 3163493 is a prime.

It is a super-2 number, since 2×3687781² = 27199457407922, which contains 22 as substring.

It is a Duffinian number.

3687781 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3687787) 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, 13945 + ... + 14206.

It is an arithmetic number, because the mean of its divisors is an integer number (929016).

Almost surely, 2^3687781 is an apocalyptic number.

It is an amenable number.

3687781 is a deficient number, since it is larger than the sum of its proper divisors (28283).

3687781 is a wasteful number, since it uses less digits than its factorization.

3687781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28282.

The product of its digits is 56448, while the sum is 40.

The square root of 3687781 is about 1920.3596017413. The cubic root of 3687781 is about 154.4975893606.

The spelling of 3687781 in words is "three million, six hundred eighty-seven thousand, seven hundred eighty-one".