1681699866 has 128 divisors (see below), whose sum is σ = 4300646400. Its totient is φ = 429327360.

The previous prime is 1681699843. The next prime is 1681699927. The reversal of 1681699866 is 6689961861.

It is a super-2 number, since 2×1681699866² = 5656228878608835912, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 3745210 + ... + 3745658.

It is an arithmetic number, because the mean of its divisors is an integer number (33598800).

Almost surely, 2^1681699866 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1681699866, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2150323200).

1681699866 is an abundant number, since it is smaller than the sum of its proper divisors (2618946534).

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

1681699866 is a wasteful number, since it uses less digits than its factorization.

1681699866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 561 (or 539 counting only the distinct ones).

The product of its digits is 6718464, while the sum is 60.

The square root of 1681699866 is about 41008.5340630460. The cubic root of 1681699866 is about 1189.1852026544.

The spelling of 1681699866 in words is "one billion, six hundred eighty-one million, six hundred ninety-nine thousand, eight hundred sixty-six".