686640044 has 12 divisors (see below), whose sum is σ = 1218081144. Its totient is φ = 338616864.

The previous prime is 686640041. The next prime is 686640067. The reversal of 686640044 is 440046686.

It is not an unprimeable number, because it can be changed into a prime (686640041) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1175462 + ... + 1176045.

It is an arithmetic number, because the mean of its divisors is an integer number (101506762).

Almost surely, 2^686640044 is an apocalyptic number.

It is an amenable number.

686640044 is a deficient number, since it is larger than the sum of its proper divisors (531441100).

686640044 is a wasteful number, since it uses less digits than its factorization.

686640044 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2351584 (or 2351582 counting only the distinct ones).

The product of its (nonzero) digits is 110592, while the sum is 38.

The square root of 686640044 is about 26203.8173554923. The cubic root of 686640044 is about 882.2189370503.

The spelling of 686640044 in words is "six hundred eighty-six million, six hundred forty thousand, forty-four".