3651691 has 4 divisors (see below), whose sum is σ = 3665152. Its totient is φ = 3638232.

The previous prime is 3651673. The next prime is 3651731. The reversal of 3651691 is 1961563.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1961563 = 41 ⋅47843.

It is a cyclic number.

It is not a de Polignac number, because 3651691 - 2¹⁹ = 3127403 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3651611) 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, 6315 + ... + 6868.

It is an arithmetic number, because the mean of its divisors is an integer number (916288).

Almost surely, 2^3651691 is an apocalyptic number.

3651691 is a deficient number, since it is larger than the sum of its proper divisors (13461).

3651691 is a wasteful number, since it uses less digits than its factorization.

3651691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13460.

The product of its digits is 4860, while the sum is 31.

The square root of 3651691 is about 1910.9398211351. The cubic root of 3651691 is about 153.9919459441.

The spelling of 3651691 in words is "three million, six hundred fifty-one thousand, six hundred ninety-one".