3636721 has 4 divisors (see below), whose sum is σ = 3967344. Its totient is φ = 3306100.

The previous prime is 3636709. The next prime is 3636757. The reversal of 3636721 is 1276363.

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.

It is a cyclic number.

It is not a de Polignac number, because 3636721 - 2⁷ = 3636593 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

3636721 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 3636721.

It is not an unprimeable number, because it can be changed into a prime (3636781) 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, 165295 + ... + 165316.

It is an arithmetic number, because the mean of its divisors is an integer number (991836).

Almost surely, 2^3636721 is an apocalyptic number.

It is an amenable number.

3636721 is a deficient number, since it is larger than the sum of its proper divisors (330623).

3636721 is a wasteful number, since it uses less digits than its factorization.

3636721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 330622.

The product of its digits is 4536, while the sum is 28.

The square root of 3636721 is about 1907.0188777251. The cubic root of 3636721 is about 153.7812292525.

The spelling of 3636721 in words is "three million, six hundred thirty-six thousand, seven hundred twenty-one".