691628818831 has 2 divisors, whose sum is σ = 691628818832. Its totient is φ = 691628818830.

The previous prime is 691628818817. The next prime is 691628818841. The reversal of 691628818831 is 138818826196.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-691628818831 is a prime.

It is a super-2 number, since 2×691628818831² (a number of 24 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 691628818831.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (691628818841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345814409415 + 345814409416.

It is an arithmetic number, because the mean of its divisors is an integer number (345814409416).

Almost surely, 2^691628818831 is an apocalyptic number.

691628818831 is a deficient number, since it is larger than the sum of its proper divisors (1).

691628818831 is an equidigital number, since it uses as much as digits as its factorization.

691628818831 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7962624, while the sum is 61.

The spelling of 691628818831 in words is "six hundred ninety-one billion, six hundred twenty-eight million, eight hundred eighteen thousand, eight hundred thirty-one".