3961949857 has 4 divisors (see below), whose sum is σ = 3962650516. Its totient is φ = 3961249200.

The previous prime is 3961949851. The next prime is 3961949879. The reversal of 3961949857 is 7589491693.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7589491693 = 7 ⋅1084213099.

It can be written as a sum of positive squares in 2 ways, for example, as 2493604096 + 1468345761 = 49936^2 + 38319^2 .

It is a cyclic number.

It is not a de Polignac number, because 3961949857 - 2¹¹ = 3961947809 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 3961949795 and 3961949804.

It is not an unprimeable number, because it can be changed into a prime (3961949851) 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, 341778 + ... + 353179.

It is an arithmetic number, because the mean of its divisors is an integer number (990662629).

Almost surely, 2^3961949857 is an apocalyptic number.

It is an amenable number.

3961949857 is a deficient number, since it is larger than the sum of its proper divisors (700659).

3961949857 is an equidigital number, since it uses as much as digits as its factorization.

3961949857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 700658.

The product of its digits is 14696640, while the sum is 61.

The square root of 3961949857 is about 62944.0216144472. The cubic root of 3961949857 is about 1582.3516038566.

The spelling of 3961949857 in words is "three billion, nine hundred sixty-one million, nine hundred forty-nine thousand, eight hundred fifty-seven".