991704385 has 36 divisors (see below), whose sum is σ = 1401103548. Its totient is φ = 671881728.

The previous prime is 991704383. The next prime is 991704407. The reversal of 991704385 is 583407199.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 699020721 + 292683664 = 26439^2 + 17108^2 .

It is not a de Polignac number, because 991704385 - 2¹ = 991704383 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (991704383) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 3128247 + ... + 3128563.

It is an arithmetic number, because the mean of its divisors is an integer number (38919543).

Almost surely, 2^991704385 is an apocalyptic number.

It is an amenable number.

991704385 is a deficient number, since it is larger than the sum of its proper divisors (409399163).

991704385 is a wasteful number, since it uses less digits than its factorization.

991704385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 562 (or 442 counting only the distinct ones).

The product of its (nonzero) digits is 272160, while the sum is 46.

The square root of 991704385 is about 31491.3382535579. The cubic root of 991704385 is about 997.2271132056.

The spelling of 991704385 in words is "nine hundred ninety-one million, seven hundred four thousand, three hundred eighty-five".