1680440451 has 4 divisors (see below), whose sum is σ = 2240587272. Its totient is φ = 1120293632.

The previous prime is 1680440441. The next prime is 1680440453. The reversal of 1680440451 is 1540440861.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1540440861 = 3 ⋅513480287.

It is a cyclic number.

It is not a de Polignac number, because 1680440451 - 2⁹ = 1680439939 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1680440453) 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, 280073406 + ... + 280073411.

It is an arithmetic number, because the mean of its divisors is an integer number (560146818).

Almost surely, 2^1680440451 is an apocalyptic number.

1680440451 is a deficient number, since it is larger than the sum of its proper divisors (560146821).

1680440451 is an equidigital number, since it uses as much as digits as its factorization.

1680440451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 560146820.

The product of its (nonzero) digits is 15360, while the sum is 33.

The square root of 1680440451 is about 40993.1756637614. The cubic root of 1680440451 is about 1188.8882706166. Note that the first 3 decimals are identical.

The spelling of 1680440451 in words is "one billion, six hundred eighty million, four hundred forty thousand, four hundred fifty-one".