856424228981 has 2 divisors, whose sum is σ = 856424228982. Its totient is φ = 856424228980.

The previous prime is 856424228977. The next prime is 856424229007. The reversal of 856424228981 is 189822424658.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 832711000900 + 23713228081 = 912530^2 + 153991^2 .

It is a cyclic number.

It is not a de Polignac number, because 856424228981 - 2² = 856424228977 is a prime.

It is a super-2 number, since 2×856424228981² (a number of 25 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 856424228981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (856424221981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 428212114490 + 428212114491.

It is an arithmetic number, because the mean of its divisors is an integer number (428212114491).

Almost surely, 2^856424228981 is an apocalyptic number.

It is an amenable number.

856424228981 is a deficient number, since it is larger than the sum of its proper divisors (1).

856424228981 is an equidigital number, since it uses as much as digits as its factorization.

856424228981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 17694720, while the sum is 59.

The spelling of 856424228981 in words is "eight hundred fifty-six billion, four hundred twenty-four million, two hundred twenty-eight thousand, nine hundred eighty-one".