3969942890861 has 2 divisors, whose sum is σ = 3969942890862. Its totient is φ = 3969942890860.

The previous prime is 3969942890839. The next prime is 3969942890917. The reversal of 3969942890861 is 1680982499693.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3946063060900 + 23879829961 = 1986470^2 + 154531^2 .

It is a cyclic number.

It is not a de Polignac number, because 3969942890861 - 2¹⁴ = 3969942874477 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3969942890821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1984971445430 + 1984971445431.

It is an arithmetic number, because the mean of its divisors is an integer number (1984971445431).

Almost surely, 2^{3969942890861} is an apocalyptic number.

It is an amenable number.

3969942890861 is a deficient number, since it is larger than the sum of its proper divisors (1).

3969942890861 is an equidigital number, since it uses as much as digits as its factorization.

3969942890861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 362797056, while the sum is 74.

The spelling of 3969942890861 in words is "three trillion, nine hundred sixty-nine billion, nine hundred forty-two million, eight hundred ninety thousand, eight hundred sixty-one".