1681445851 has 8 divisors (see below), whose sum is σ = 1700407904. Its totient is φ = 1662534720.

The previous prime is 1681445849. The next prime is 1681445861. The reversal of 1681445851 is 1585441861.

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

It is a cyclic number.

It is not a de Polignac number, because 1681445851 - 2¹ = 1681445849 is a prime.

It is a super-2 number, since 2×1681445851² = 5654520299690228402, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1681445798 and 1681445807.

It is not an unprimeable number, because it can be changed into a prime (1681445861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 55735 + ... + 80431.

It is an arithmetic number, because the mean of its divisors is an integer number (212550988).

Almost surely, 2^1681445851 is an apocalyptic number.

1681445851 is the 23675-th hex number.

1681445851 is a deficient number, since it is larger than the sum of its proper divisors (18962053).

1681445851 is a wasteful number, since it uses less digits than its factorization.

1681445851 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25461.

The product of its digits is 153600, while the sum is 43.

The square root of 1681445851 is about 41005.4368468378. The cubic root of 1681445851 is about 1189.1253255234.

The spelling of 1681445851 in words is "one billion, six hundred eighty-one million, four hundred forty-five thousand, eight hundred fifty-one".