681991711 has 2 divisors, whose sum is σ = 681991712. Its totient is φ = 681991710.

The previous prime is 681991657. The next prime is 681991721. The reversal of 681991711 is 117199186.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 681991711 - 2¹⁵ = 681958943 is a prime.

It is a super-2 number, since 2×681991711² = 930225387745415042, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (681991721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340995855 + 340995856.

It is an arithmetic number, because the mean of its divisors is an integer number (340995856).

Almost surely, 2^681991711 is an apocalyptic number.

681991711 is a deficient number, since it is larger than the sum of its proper divisors (1).

681991711 is an equidigital number, since it uses as much as digits as its factorization.

681991711 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27216, while the sum is 43.

The square root of 681991711 is about 26114.9710128118. The cubic root of 681991711 is about 880.2236479598.

The spelling of 681991711 in words is "six hundred eighty-one million, nine hundred ninety-one thousand, seven hundred eleven".