661206253 has 2 divisors, whose sum is σ = 661206254. Its totient is φ = 661206252.

The previous prime is 661206239. The next prime is 661206263. The reversal of 661206253 is 352602166.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 606045924 + 55160329 = 24618^2 + 7427^2 .

It is a cyclic number.

It is not a de Polignac number, because 661206253 - 2¹³ = 661198061 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661206233) 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, 330603126 + 330603127.

It is an arithmetic number, because the mean of its divisors is an integer number (330603127).

Almost surely, 2^661206253 is an apocalyptic number.

It is an amenable number.

661206253 is a deficient number, since it is larger than the sum of its proper divisors (1).

661206253 is an equidigital number, since it uses as much as digits as its factorization.

661206253 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12960, while the sum is 31.

The square root of 661206253 is about 25713.9311074756. The cubic root of 661206253 is about 871.1888678944.

The spelling of 661206253 in words is "six hundred sixty-one million, two hundred six thousand, two hundred fifty-three".