691423625 has 16 divisors (see below), whose sum is σ = 886224144. Its totient is φ = 538185600.

The previous prime is 691423559. The next prime is 691423651. The reversal of 691423625 is 526324196.

It can be written as a sum of positive squares in 8 ways, for example, as 196672576 + 494751049 = 14024^2 + 22243^2 .

It is not a de Polignac number, because 691423625 - 2¹⁰ = 691422601 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 70124 + ... + 79373.

It is an arithmetic number, because the mean of its divisors is an integer number (55389009).

Almost surely, 2^691423625 is an apocalyptic number.

It is an amenable number.

691423625 is a deficient number, since it is larger than the sum of its proper divisors (194800519).

691423625 is a wasteful number, since it uses less digits than its factorization.

691423625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 149549 (or 149539 counting only the distinct ones).

The product of its digits is 77760, while the sum is 38.

The square root of 691423625 is about 26294.9353488462. The cubic root of 691423625 is about 884.2629014230.

The spelling of 691423625 in words is "six hundred ninety-one million, four hundred twenty-three thousand, six hundred twenty-five".