891956621629 has 2 divisors, whose sum is σ = 891956621630. Its totient is φ = 891956621628.

The previous prime is 891956621627. The next prime is 891956621653. The reversal of 891956621629 is 926126659198.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 616378869604 + 275577752025 = 785098^2 + 524955^2 .

It is a cyclic number.

It is not a de Polignac number, because 891956621629 - 2¹ = 891956621627 is a prime.

It is a super-2 number, since 2×891956621629² (a number of 25 digits) contains 22 as substring.

Together with 891956621627, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (891956621627) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 445978310814 + 445978310815.

It is an arithmetic number, because the mean of its divisors is an integer number (445978310815).

Almost surely, 2^891956621629 is an apocalyptic number.

It is an amenable number.

891956621629 is a deficient number, since it is larger than the sum of its proper divisors (1).

891956621629 is an equidigital number, since it uses as much as digits as its factorization.

891956621629 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 25194240, while the sum is 64.

The spelling of 891956621629 in words is "eight hundred ninety-one billion, nine hundred fifty-six million, six hundred twenty-one thousand, six hundred twenty-nine".