1172721917 has 2 divisors, whose sum is σ = 1172721918. Its totient is φ = 1172721916.

The previous prime is 1172721911. The next prime is 1172721941. The reversal of 1172721917 is 7191272711.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1171966756 + 755161 = 34234^2 + 869^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1172721917 is a prime.

It is a super-2 number, since 2×1172721917² = 2750553389224309778, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1172721911) 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, 586360958 + 586360959.

It is an arithmetic number, because the mean of its divisors is an integer number (586360959).

Almost surely, 2^1172721917 is an apocalyptic number.

It is an amenable number.

1172721917 is a deficient number, since it is larger than the sum of its proper divisors (1).

1172721917 is an equidigital number, since it uses as much as digits as its factorization.

1172721917 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12348, while the sum is 38.

The square root of 1172721917 is about 34245.0276244596. The cubic root of 1172721917 is about 1054.5447500101.

The spelling of 1172721917 in words is "one billion, one hundred seventy-two million, seven hundred twenty-one thousand, nine hundred seventeen".