661364237 has 2 divisors, whose sum is σ = 661364238. Its totient is φ = 661364236.

The previous prime is 661364191. The next prime is 661364239. The reversal of 661364237 is 732463166.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 551827081 + 109537156 = 23491^2 + 10466^2 .

It is a cyclic number.

It is not a de Polignac number, because 661364237 - 2²⁰ = 660315661 is a prime.

Together with 661364239, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 661364237.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661364239) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330682118 + 330682119.

It is an arithmetic number, because the mean of its divisors is an integer number (330682119).

Almost surely, 2^661364237 is an apocalyptic number.

It is an amenable number.

661364237 is a deficient number, since it is larger than the sum of its proper divisors (1).

661364237 is an equidigital number, since it uses as much as digits as its factorization.

661364237 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 108864, while the sum is 38.

The square root of 661364237 is about 25717.0028774739. The cubic root of 661364237 is about 871.2582476283.

The spelling of 661364237 in words is "six hundred sixty-one million, three hundred sixty-four thousand, two hundred thirty-seven".