656628826661 has 2 divisors, whose sum is σ = 656628826662. Its totient is φ = 656628826660.

The previous prime is 656628826631. The next prime is 656628826663. The reversal of 656628826661 is 166628826656.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 497292936100 + 159335890561 = 705190^2 + 399169^2 .

It is a cyclic number.

It is not a de Polignac number, because 656628826661 - 2⁶ = 656628826597 is a prime.

It is a super-2 number, since 2×656628826661² (a number of 24 digits) contains 22 as substring.

Together with 656628826663, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 656628826594 and 656628826603.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (656628826663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 328314413330 + 328314413331.

It is an arithmetic number, because the mean of its divisors is an integer number (328314413331).

Almost surely, 2^656628826661 is an apocalyptic number.

It is an amenable number.

656628826661 is a deficient number, since it is larger than the sum of its proper divisors (1).

656628826661 is an equidigital number, since it uses as much as digits as its factorization.

656628826661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 59719680, while the sum is 62.

The spelling of 656628826661 in words is "six hundred fifty-six billion, six hundred twenty-eight million, eight hundred twenty-six thousand, six hundred sixty-one".