20661265507 has 2 divisors, whose sum is σ = 20661265508. Its totient is φ = 20661265506.

The previous prime is 20661265487. The next prime is 20661265511. The reversal of 20661265507 is 70556216602.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20661265507 - 2¹¹ = 20661263459 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20661265507.

It is not a weakly prime, because it can be changed into another prime (20661265567) 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, 10330632753 + 10330632754.

It is an arithmetic number, because the mean of its divisors is an integer number (10330632754).

Almost surely, 2^20661265507 is an apocalyptic number.

20661265507 is a deficient number, since it is larger than the sum of its proper divisors (1).

20661265507 is an equidigital number, since it uses as much as digits as its factorization.

20661265507 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 151200, while the sum is 40.

The spelling of 20661265507 in words is "twenty billion, six hundred sixty-one million, two hundred sixty-five thousand, five hundred seven".