6921075855157 has 2 divisors, whose sum is σ = 6921075855158. Its totient is φ = 6921075855156.

The previous prime is 6921075855107. The next prime is 6921075855251. The reversal of 6921075855157 is 7515585701296.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3821923340676 + 3099152514481 = 1954974^2 + 1760441^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6921075855157 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 6921075855095 and 6921075855104.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6921075855107) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3460537927578 + 3460537927579.

It is an arithmetic number, because the mean of its divisors is an integer number (3460537927579).

Almost surely, 2^{6921075855157} is an apocalyptic number.

It is an amenable number.

6921075855157 is a deficient number, since it is larger than the sum of its proper divisors (1).

6921075855157 is an equidigital number, since it uses as much as digits as its factorization.

6921075855157 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 26460000, while the sum is 61.

The spelling of 6921075855157 in words is "six trillion, nine hundred twenty-one billion, seventy-five million, eight hundred fifty-five thousand, one hundred fifty-seven".