1906888728581 has 2 divisors, whose sum is σ = 1906888728582. Its totient is φ = 1906888728580.

The previous prime is 1906888728551. The next prime is 1906888728601. The reversal of 1906888728581 is 1858278886091.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1900455244900 + 6433483681 = 1378570^2 + 80209^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1906888728581 is a prime.

It is a super-2 number, since 2×1906888728581² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1906888728551) 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, 953444364290 + 953444364291.

It is an arithmetic number, because the mean of its divisors is an integer number (953444364291).

Almost surely, 2^{1906888728581} is an apocalyptic number.

It is an amenable number.

1906888728581 is a deficient number, since it is larger than the sum of its proper divisors (1).

1906888728581 is an equidigital number, since it uses as much as digits as its factorization.

1906888728581 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 123863040, while the sum is 71.

The spelling of 1906888728581 in words is "one trillion, nine hundred six billion, eight hundred eighty-eight million, seven hundred twenty-eight thousand, five hundred eighty-one".