681522449 has 2 divisors, whose sum is σ = 681522450. Its totient is φ = 681522448.

The previous prime is 681522403. The next prime is 681522463. The reversal of 681522449 is 944225186.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 633428224 + 48094225 = 25168^2 + 6935^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-681522449 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (681522349) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340761224 + 340761225.

It is an arithmetic number, because the mean of its divisors is an integer number (340761225).

Almost surely, 2^681522449 is an apocalyptic number.

It is an amenable number.

681522449 is a deficient number, since it is larger than the sum of its proper divisors (1).

681522449 is an equidigital number, since it uses as much as digits as its factorization.

681522449 is an evil number, because the sum of its binary digits is even.

The product of its digits is 138240, while the sum is 41.

The square root of 681522449 is about 26105.9849268324. The cubic root of 681522449 is about 880.0217147706.

The spelling of 681522449 in words is "six hundred eighty-one million, five hundred twenty-two thousand, four hundred forty-nine".