2081691890 has 8 divisors (see below), whose sum is σ = 3747045420. Its totient is φ = 832676752.

The previous prime is 2081691869. The next prime is 2081691929. The reversal of 2081691890 is 981961802.

It can be written as a sum of positive squares in 2 ways, for example, as 1959567289 + 122124601 = 44267^2 + 11051^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×2081691890² = 8666882249783544200, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 104084585 + ... + 104084604.

Almost surely, 2^2081691890 is an apocalyptic number.

2081691890 is a deficient number, since it is larger than the sum of its proper divisors (1665353530).

2081691890 is a wasteful number, since it uses less digits than its factorization.

2081691890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 208169196.

The product of its (nonzero) digits is 62208, while the sum is 44.

The square root of 2081691890 is about 45625.5618047603. The cubic root of 2081691890 is about 1276.8468715879.

The spelling of 2081691890 in words is "two billion, eighty-one million, six hundred ninety-one thousand, eight hundred ninety".