139756666358021 has 2 divisors, whose sum is σ = 139756666358022. Its totient is φ = 139756666358020.

The previous prime is 139756666357927. The next prime is 139756666358107. The reversal of 139756666358021 is 120853666657931.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 131425909804996 + 8330756553025 = 11464114^2 + 2886305^2 .

It is a cyclic number.

It is not a de Polignac number, because 139756666358021 - 2¹⁴ = 139756666341637 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (139756666318021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69878333179010 + 69878333179011.

It is an arithmetic number, because the mean of its divisors is an integer number (69878333179011).

Almost surely, 2^{139756666358021} is an apocalyptic number.

It is an amenable number.

139756666358021 is a deficient number, since it is larger than the sum of its proper divisors (1).

139756666358021 is an equidigital number, since it uses as much as digits as its factorization.

139756666358021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 293932800, while the sum is 68.

The spelling of 139756666358021 in words is "one hundred thirty-nine trillion, seven hundred fifty-six billion, six hundred sixty-six million, three hundred fifty-eight thousand, twenty-one".