691319440644 has 24 divisors (see below), whose sum is σ = 1843518508608. Its totient is φ = 197519840160.

The previous prime is 691319440631. The next prime is 691319440697. The reversal of 691319440644 is 446044913196.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4114996587 + ... + 4114996754.

It is an arithmetic number, because the mean of its divisors is an integer number (76813271192).

Almost surely, 2^691319440644 is an apocalyptic number.

It is an amenable number.

691319440644 is an abundant number, since it is smaller than the sum of its proper divisors (1152199067964).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

691319440644 is a wasteful number, since it uses less digits than its factorization.

691319440644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8229993355 (or 8229993353 counting only the distinct ones).

The product of its (nonzero) digits is 2239488, while the sum is 51.

The spelling of 691319440644 in words is "six hundred ninety-one billion, three hundred nineteen million, four hundred forty thousand, six hundred forty-four".