681262513 has 2 divisors, whose sum is σ = 681262514. Its totient is φ = 681262512.

The previous prime is 681262511. The next prime is 681262523. The reversal of 681262513 is 315262186.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 663217009 + 18045504 = 25753^2 + 4248^2 .

It is a cyclic number.

It is not a de Polignac number, because 681262513 - 2¹ = 681262511 is a prime.

It is a super-2 number, since 2×681262513² = 928237223238150338, which contains 22 as substring.

Together with 681262511, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (681262511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340631256 + 340631257.

It is an arithmetic number, because the mean of its divisors is an integer number (340631257).

Almost surely, 2^681262513 is an apocalyptic number.

It is an amenable number.

681262513 is a deficient number, since it is larger than the sum of its proper divisors (1).

681262513 is an equidigital number, since it uses as much as digits as its factorization.

681262513 is an evil number, because the sum of its binary digits is even.

The product of its digits is 17280, while the sum is 34.

The square root of 681262513 is about 26101.0059767818. The cubic root of 681262513 is about 879.9098190128.

The spelling of 681262513 in words is "six hundred eighty-one million, two hundred sixty-two thousand, five hundred thirteen".