661674749 has 2 divisors, whose sum is σ = 661674750. Its totient is φ = 661674748.

The previous prime is 661674743. The next prime is 661674763. The reversal of 661674749 is 947476166.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 477204025 + 184470724 = 21845^2 + 13582^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-661674749 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 661674697 and 661674706.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661674743) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330837374 + 330837375.

It is an arithmetic number, because the mean of its divisors is an integer number (330837375).

Almost surely, 2^661674749 is an apocalyptic number.

It is an amenable number.

661674749 is a deficient number, since it is larger than the sum of its proper divisors (1).

661674749 is an equidigital number, since it uses as much as digits as its factorization.

661674749 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1524096, while the sum is 50.

The square root of 661674749 is about 25723.0392644415. The cubic root of 661674749 is about 871.3945788650.

The spelling of 661674749 in words is "six hundred sixty-one million, six hundred seventy-four thousand, seven hundred forty-nine".