1855216868929 has 2 divisors, whose sum is σ = 1855216868930. Its totient is φ = 1855216868928.

The previous prime is 1855216868863. The next prime is 1855216868993. The reversal of 1855216868929 is 9298686125581.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1642119228304 + 213097640625 = 1281452^2 + 461625^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1855216868929 is a prime.

It is a super-3 number, since 3×1855216868929³ (a number of 38 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (1855216868129) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 927608434464 + 927608434465.

It is an arithmetic number, because the mean of its divisors is an integer number (927608434465).

Almost surely, 2^{1855216868929} is an apocalyptic number.

It is an amenable number.

1855216868929 is a deficient number, since it is larger than the sum of its proper divisors (1).

1855216868929 is an equidigital number, since it uses as much as digits as its factorization.

1855216868929 is an evil number, because the sum of its binary digits is even.

The product of its digits is 149299200, while the sum is 70.

The spelling of 1855216868929 in words is "one trillion, eight hundred fifty-five billion, two hundred sixteen million, eight hundred sixty-eight thousand, nine hundred twenty-nine".