840100661 has 2 divisors, whose sum is σ = 840100662. Its totient is φ = 840100660.

The previous prime is 840100643. The next prime is 840100669. The reversal of 840100661 is 166001048.

840100661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 755920036 + 84180625 = 27494^2 + 9175^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-840100661 is a prime.

It is a super-2 number, since 2×840100661² = 1411538241225273842, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 840100661.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (840100669) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 420050330 + 420050331.

It is an arithmetic number, because the mean of its divisors is an integer number (420050331).

Almost surely, 2^840100661 is an apocalyptic number.

It is an amenable number.

840100661 is a deficient number, since it is larger than the sum of its proper divisors (1).

840100661 is an equidigital number, since it uses as much as digits as its factorization.

840100661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1152, while the sum is 26.

The square root of 840100661 is about 28984.4900075885. The cubic root of 840100661 is about 943.5764840653.

The spelling of 840100661 in words is "eight hundred forty million, one hundred thousand, six hundred sixty-one".