661966337 has 2 divisors, whose sum is σ = 661966338. Its totient is φ = 661966336.

The previous prime is 661966321. The next prime is 661966339. The reversal of 661966337 is 733669166.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 461347441 + 200618896 = 21479^2 + 14164^2 .

661966337 is a truncatable prime.

It is a cyclic number.

It is not a de Polignac number, because 661966337 - 2⁴ = 661966321 is a prime.

Together with 661966339, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 661966291 and 661966300.

It is not a weakly prime, because it can be changed into another prime (661966339) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330983168 + 330983169.

It is an arithmetic number, because the mean of its divisors is an integer number (330983169).

Almost surely, 2^661966337 is an apocalyptic number.

It is an amenable number.

661966337 is a deficient number, since it is larger than the sum of its proper divisors (1).

661966337 is an equidigital number, since it uses as much as digits as its factorization.

661966337 is an evil number, because the sum of its binary digits is even.

The product of its digits is 734832, while the sum is 47.

The square root of 661966337 is about 25728.7064773960. The cubic root of 661966337 is about 871.5225626354.

The spelling of 661966337 in words is "six hundred sixty-one million, nine hundred sixty-six thousand, three hundred thirty-seven".