826678921661 has 2 divisors, whose sum is σ = 826678921662. Its totient is φ = 826678921660.

The previous prime is 826678921583. The next prime is 826678921759. The reversal of 826678921661 is 166129876628.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 497123704900 + 329555216761 = 705070^2 + 574069^2 .

It is a cyclic number.

It is not a de Polignac number, because 826678921661 - 2²² = 826674727357 is a prime.

It is a super-5 number, since 5×826678921661⁵ (a number of 61 digits) contains 55555 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 826678921594 and 826678921603.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (826678923661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 413339460830 + 413339460831.

It is an arithmetic number, because the mean of its divisors is an integer number (413339460831).

Almost surely, 2^826678921661 is an apocalyptic number.

It is an amenable number.

826678921661 is a deficient number, since it is larger than the sum of its proper divisors (1).

826678921661 is an equidigital number, since it uses as much as digits as its factorization.

826678921661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20901888, while the sum is 62.

The spelling of 826678921661 in words is "eight hundred twenty-six billion, six hundred seventy-eight million, nine hundred twenty-one thousand, six hundred sixty-one".