661428505824139 has 2 divisors, whose sum is σ = 661428505824140. Its totient is φ = 661428505824138.

The previous prime is 661428505824103. The next prime is 661428505824311. The reversal of 661428505824139 is 931428505824166.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 661428505824139 - 2¹³ = 661428505815947 is a prime.

It is not a weakly prime, because it can be changed into another prime (661428505804139) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330714252912069 + 330714252912070.

It is an arithmetic number, because the mean of its divisors is an integer number (330714252912070).

Almost surely, 2^{661428505824139} is an apocalyptic number.

661428505824139 is a deficient number, since it is larger than the sum of its proper divisors (1).

661428505824139 is an equidigital number, since it uses as much as digits as its factorization.

661428505824139 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 99532800, while the sum is 64.

The spelling of 661428505824139 in words is "six hundred sixty-one trillion, four hundred twenty-eight billion, five hundred five million, eight hundred twenty-four thousand, one hundred thirty-nine".