1691312193409 has 2 divisors, whose sum is σ = 1691312193410. Its totient is φ = 1691312193408.

The previous prime is 1691312193323. The next prime is 1691312193419. The reversal of 1691312193409 is 9043912131961.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1690332816384 + 979377025 = 1300128^2 + 31295^2 .

It is a cyclic number.

It is not a de Polignac number, because 1691312193409 - 2²¹ = 1691310096257 is a prime.

It is not a weakly prime, because it can be changed into another prime (1691312193419) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 845656096704 + 845656096705.

It is an arithmetic number, because the mean of its divisors is an integer number (845656096705).

Almost surely, 2^{1691312193409} is an apocalyptic number.

It is an amenable number.

1691312193409 is a deficient number, since it is larger than the sum of its proper divisors (1).

1691312193409 is an equidigital number, since it uses as much as digits as its factorization.

1691312193409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 314928, while the sum is 49.

The spelling of 1691312193409 in words is "one trillion, six hundred ninety-one billion, three hundred twelve million, one hundred ninety-three thousand, four hundred nine".