1681265664 has 132 divisors (see below), whose sum is σ = 5228422836. Its totient is φ = 517275648.

The previous prime is 1681265549. The next prime is 1681265669. The reversal of 1681265664 is 4665621861.

1681265664 is a `hidden beast` number, since 1 + 6 + 81 + 2 + 6 + 566 + 4 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 221414400 + 1459851264 = 14880^2 + 38208^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1681265669) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 112792 + ... + 126824.

Almost surely, 2^1681265664 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1681265664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2614211418).

1681265664 is an abundant number, since it is smaller than the sum of its proper divisors (3547157172).

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

1681265664 is a wasteful number, since it uses less digits than its factorization.

1681265664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14072 (or 14051 counting only the distinct ones).

The product of its digits is 414720, while the sum is 45.

The square root of 1681265664 is about 41003.2396768841. The cubic root of 1681265664 is about 1189.0828476803.

The spelling of 1681265664 in words is "one billion, six hundred eighty-one million, two hundred sixty-five thousand, six hundred sixty-four".