1681331861 has 4 divisors (see below), whose sum is σ = 1834180224. Its totient is φ = 1528483500.

The previous prime is 1681331851. The next prime is 1681331881.

1681331861 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1681331861 - 2¹⁴ = 1681315477 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1681331801) 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, 76424165 + ... + 76424186.

It is an arithmetic number, because the mean of its divisors is an integer number (458545056).

Almost surely, 2^1681331861 is an apocalyptic number.

1681331861 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1681331861 is a deficient number, since it is larger than the sum of its proper divisors (152848363).

1681331861 is a wasteful number, since it uses less digits than its factorization.

1681331861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 152848362.

The product of its digits is 20736, while the sum is 38.

The square root of 1681331861 is about 41004.0468856429. The cubic root of 1681331861 is about 1189.0984535194.

The spelling of 1681331861 in words is "one billion, six hundred eighty-one million, three hundred thirty-one thousand, eight hundred sixty-one".