991611373 has 2 divisors, whose sum is σ = 991611374. Its totient is φ = 991611372.

The previous prime is 991611367. The next prime is 991611391. The reversal of 991611373 is 373116199.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 594286884 + 397324489 = 24378^2 + 19933^2 .

It is a cyclic number.

It is not a de Polignac number, because 991611373 - 2²¹ = 989514221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (991611073) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495805686 + 495805687.

It is an arithmetic number, because the mean of its divisors is an integer number (495805687).

Almost surely, 2^991611373 is an apocalyptic number.

It is an amenable number.

991611373 is a deficient number, since it is larger than the sum of its proper divisors (1).

991611373 is an equidigital number, since it uses as much as digits as its factorization.

991611373 is an evil number, because the sum of its binary digits is even.

The product of its digits is 30618, while the sum is 40.

The square root of 991611373 is about 31489.8614318958. The cubic root of 991611373 is about 997.1959355719.

The spelling of 991611373 in words is "nine hundred ninety-one million, six hundred eleven thousand, three hundred seventy-three".