4020661 has 4 divisors (see below), whose sum is σ = 4024800. Its totient is φ = 4016524.

The previous prime is 4020641. The next prime is 4020671. The reversal of 4020661 is 1660204.

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 a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-4020661 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4020631) 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, 270 + ... + 2848.

It is an arithmetic number, because the mean of its divisors is an integer number (1006200).

Almost surely, 2^4020661 is an apocalyptic number.

It is an amenable number.

4020661 is a deficient number, since it is larger than the sum of its proper divisors (4139).

4020661 is a wasteful number, since it uses less digits than its factorization.

4020661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4138.

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 4020661 is about 2005.1585972187. The cubic root of 4020661 is about 159.0129467458.

Adding to 4020661 its reverse (1660204), we get a palindrome (5680865).

The spelling of 4020661 in words is "four million, twenty thousand, six hundred sixty-one".