1691274779 has 2 divisors, whose sum is σ = 1691274780. Its totient is φ = 1691274778.

The previous prime is 1691274671. The next prime is 1691274803. The reversal of 1691274779 is 9774721961.

It is a happy number.

It is a strong prime.

It is an emirp because it is prime and its reverse (9774721961) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1691274779 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1691274779.

It is not a weakly prime, because it can be changed into another prime (1691277779) 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, 845637389 + 845637390.

It is an arithmetic number, because the mean of its divisors is an integer number (845637390).

Almost surely, 2^1691274779 is an apocalyptic number.

1691274779 is a deficient number, since it is larger than the sum of its proper divisors (1).

1691274779 is an equidigital number, since it uses as much as digits as its factorization.

1691274779 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1333584, while the sum is 53.

The square root of 1691274779 is about 41125.1112946822. Note that the first 3 decimals coincide. The cubic root of 1691274779 is about 1191.4378446483.

The spelling of 1691274779 in words is "one billion, six hundred ninety-one million, two hundred seventy-four thousand, seven hundred seventy-nine".