691458025543 has 2 divisors, whose sum is σ = 691458025544. Its totient is φ = 691458025542.

The previous prime is 691458025429. The next prime is 691458025549. The reversal of 691458025543 is 345520854196.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-691458025543 is a prime.

It is a super-2 number, since 2×691458025543² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (691458025549) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345729012771 + 345729012772.

It is an arithmetic number, because the mean of its divisors is an integer number (345729012772).

Almost surely, 2^691458025543 is an apocalyptic number.

691458025543 is a deficient number, since it is larger than the sum of its proper divisors (1).

691458025543 is an equidigital number, since it uses as much as digits as its factorization.

691458025543 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184000, while the sum is 52.

The spelling of 691458025543 in words is "six hundred ninety-one billion, four hundred fifty-eight million, twenty-five thousand, five hundred forty-three".