3949297661 has 2 divisors, whose sum is σ = 3949297662. Its totient is φ = 3949297660.

The previous prime is 3949297621. The next prime is 3949297679. The reversal of 3949297661 is 1667929493.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3835448761 + 113848900 = 61931^2 + 10670^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-3949297661 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 3949297597 and 3949297606.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3949297621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1974648830 + 1974648831.

It is an arithmetic number, because the mean of its divisors is an integer number (1974648831).

Almost surely, 2^3949297661 is an apocalyptic number.

It is an amenable number.

3949297661 is a deficient number, since it is larger than the sum of its proper divisors (1).

3949297661 is an equidigital number, since it uses as much as digits as its factorization.

3949297661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4408992, while the sum is 56.

The square root of 3949297661 is about 62843.4376924114. The cubic root of 3949297661 is about 1580.6654331340.

The spelling of 3949297661 in words is "three billion, nine hundred forty-nine million, two hundred ninety-seven thousand, six hundred sixty-one".