687181644 has 48 divisors (see below), whose sum is σ = 1803599840. Its totient is φ = 229057632.

The previous prime is 687181639. The next prime is 687181661. The reversal of 687181644 is 446181786.

It is a super-2 number, since 2×687181644² = 944437223701085472, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 687181644.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 30529 + ... + 48024.

Almost surely, 2^687181644 is an apocalyptic number.

It is an amenable number.

687181644 is an abundant number, since it is smaller than the sum of its proper divisors (1116418196).

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

687181644 is an equidigital number, since it uses as much as digits as its factorization.

687181644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78578 (or 78558 counting only the distinct ones).

The product of its digits is 258048, while the sum is 45.

The square root of 687181644 is about 26214.1496905774. The cubic root of 687181644 is about 882.4508315770.

The spelling of 687181644 in words is "six hundred eighty-seven million, one hundred eighty-one thousand, six hundred forty-four".