691538985 has 32 divisors (see below), whose sum is σ = 1244234880. Its totient is φ = 364371264.

The previous prime is 691538983. The next prime is 691539007. The reversal of 691538985 is 589835196.

It is a happy number.

It is not a de Polignac number, because 691538985 - 2¹ = 691538983 is a prime.

It is not an unprimeable number, because it can be changed into a prime (691538983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 19654 + ... + 42063.

It is an arithmetic number, because the mean of its divisors is an integer number (38882340).

Almost surely, 2^691538985 is an apocalyptic number.

It is an amenable number.

691538985 is a deficient number, since it is larger than the sum of its proper divisors (552695895).

691538985 is a wasteful number, since it uses less digits than its factorization.

691538985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61814 (or 61808 counting only the distinct ones).

The product of its digits is 2332800, while the sum is 54.

The square root of 691538985 is about 26297.1288356733. The cubic root of 691538985 is about 884.3120767244.

The spelling of 691538985 in words is "six hundred ninety-one million, five hundred thirty-eight thousand, nine hundred eighty-five".