681543444 has 12 divisors (see below), whose sum is σ = 1590268064. Its totient is φ = 227181144.

The previous prime is 681543427. The next prime is 681543449. The reversal of 681543444 is 444345186.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×681543444² = 929002932118762272, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681543449) 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, 28397632 + ... + 28397655.

Almost surely, 2^681543444 is an apocalyptic number.

It is an amenable number.

681543444 is an abundant number, since it is smaller than the sum of its proper divisors (908724620).

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

681543444 is a wasteful number, since it uses less digits than its factorization.

681543444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56795294 (or 56795292 counting only the distinct ones).

The product of its digits is 184320, while the sum is 39.

The square root of 681543444 is about 26106.3870345937. The cubic root of 681543444 is about 880.0307513359.

The spelling of 681543444 in words is "six hundred eighty-one million, five hundred forty-three thousand, four hundred forty-four".