3651921 has 45 divisors (see below), whose sum is σ = 6663579. Its totient is φ = 1926288.

The previous prime is 3651919. The next prime is 3651929. The reversal of 3651921 is 1291563.

The square root of 3651921 is 1911.

It is a perfect power (a square), and thus also a powerful number.

3651921 is a `hidden beast` number, since 3 + 651 + 9 + 2 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 540225 + 3111696 = 735^2 + 1764^2 .

It is not a de Polignac number, because 3651921 - 2¹ = 3651919 is a prime.

Its product of digits (1620) is a multiple of the sum of its prime factors (60).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (3651929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 280911 + ... + 280923.

Almost surely, 2^3651921 is an apocalyptic number.

3651921 is the 1911-st square number.

3651921 is the 956-th centered octagonal number.

It is an amenable number.

3651921 is a deficient number, since it is larger than the sum of its proper divisors (3011658).

3651921 is an equidigital number, since it uses as much as digits as its factorization.

3651921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60 (or 23 counting only the distinct ones).

The product of its digits is 1620, while the sum is 27.

The cubic root of 3651921 is about 153.9951789124.

The spelling of 3651921 in words is "three million, six hundred fifty-one thousand, nine hundred twenty-one".