681451 has 2 divisors, whose sum is σ = 681452. Its totient is φ = 681450.

The previous prime is 681449. The next prime is 681481. The reversal of 681451 is 154186.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 681451 - 2¹ = 681449 is a prime.

Together with 681449, it forms a pair of twin primes.

It is the 826-th Hogben number.

It is not a weakly prime, because it can be changed into another prime (681481) by changing a digit.

It is a nontrivial repunit in base 825.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340725 + 340726.

It is an arithmetic number, because the mean of its divisors is an integer number (340726).

2⁶⁸¹⁴⁵¹ is an apocalyptic number.

681451 is a deficient number, since it is larger than the sum of its proper divisors (1).

681451 is an equidigital number, since it uses as much as digits as its factorization.

681451 is an evil number, because the sum of its binary digits is even.

The product of its digits is 960, while the sum is 25.

The square root of 681451 is about 825.5004542700. The cubic root of 681451 is about 87.9990960651. Note that the first 3 decimals are identical.

The spelling of 681451 in words is "six hundred eighty-one thousand, four hundred fifty-one".