3642721 has 2 divisors, whose sum is σ = 3642722. Its totient is φ = 3642720.

The previous prime is 3642707. The next prime is 3642731. The reversal of 3642721 is 1272463.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1860496 + 1782225 = 1364^2 + 1335^2 .

It is a cyclic number.

It is not a de Polignac number, because 3642721 - 2⁹ = 3642209 is a prime.

It is not a weakly prime, because it can be changed into another prime (3642701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1821360 + 1821361.

It is an arithmetic number, because the mean of its divisors is an integer number (1821361).

Almost surely, 2^3642721 is an apocalyptic number.

It is an amenable number.

3642721 is a deficient number, since it is larger than the sum of its proper divisors (1).

3642721 is an equidigital number, since it uses as much as digits as its factorization.

3642721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2016, while the sum is 25.

The square root of 3642721 is about 1908.5913653792. The cubic root of 3642721 is about 153.8657541502.

The spelling of 3642721 in words is "three million, six hundred forty-two thousand, seven hundred twenty-one".