691242985 has 16 divisors (see below), whose sum is σ = 879031440. Its totient is φ = 520898560.

The previous prime is 691242983. The next prime is 691243019. The reversal of 691242985 is 589242196.

It can be written as a sum of positive squares in 8 ways, for example, as 7054336 + 684188649 = 2656^2 + 26157^2 .

It is not a de Polignac number, because 691242985 - 2¹ = 691242983 is a prime.

It is not an unprimeable number, because it can be changed into a prime (691242983) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 52192 + ... + 64081.

It is an arithmetic number, because the mean of its divisors is an integer number (54939465).

Almost surely, 2^691242985 is an apocalyptic number.

It is an amenable number.

691242985 is a deficient number, since it is larger than the sum of its proper divisors (187788455).

691242985 is a wasteful number, since it uses less digits than its factorization.

691242985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 116348.

The product of its digits is 311040, while the sum is 46.

The square root of 691242985 is about 26291.5002424738. The cubic root of 691242985 is about 884.1858877769.

The spelling of 691242985 in words is "six hundred ninety-one million, two hundred forty-two thousand, nine hundred eighty-five".