6661901 has 2 divisors, whose sum is σ = 6661902. Its totient is φ = 6661900.

The previous prime is 6661891. The next prime is 6661933. The reversal of 6661901 is 1091666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6100900 + 561001 = 2470^2 + 749^2 .

It is a cyclic number.

It is not a de Polignac number, because 6661901 - 2¹⁴ = 6645517 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6661301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3330950 + 3330951.

It is an arithmetic number, because the mean of its divisors is an integer number (3330951).

Almost surely, 2^6661901 is an apocalyptic number.

It is an amenable number.

6661901 is a deficient number, since it is larger than the sum of its proper divisors (1).

6661901 is an equidigital number, since it uses as much as digits as its factorization.

6661901 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1944, while the sum is 29.

The square root of 6661901 is about 2581.0658651030. The cubic root of 6661901 is about 188.1623484454.

The spelling of 6661901 in words is "six million, six hundred sixty-one thousand, nine hundred one".