681148978644 has 24 divisors (see below), whose sum is σ = 1601480045088. Its totient is φ = 225316455520.

The previous prime is 681148978589. The next prime is 681148978649. The reversal of 681148978644 is 446879841186.

It is a super-2 number, since 2×681148978644² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681148978649) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 216648867 + ... + 216652010.

It is an arithmetic number, because the mean of its divisors is an integer number (66728335212).

Almost surely, 2^681148978644 is an apocalyptic number.

It is an amenable number.

681148978644 is an abundant number, since it is smaller than the sum of its proper divisors (920331066444).

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

681148978644 is a wasteful number, since it uses less digits than its factorization.

681148978644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 433301015 (or 433301013 counting only the distinct ones).

The product of its digits is 74317824, while the sum is 66.

The spelling of 681148978644 in words is "six hundred eighty-one billion, one hundred forty-eight million, nine hundred seventy-eight thousand, six hundred forty-four".