1906326581 has 2 divisors, whose sum is σ = 1906326582. Its totient is φ = 1906326580.

The previous prime is 1906326577. The next prime is 1906326589. The reversal of 1906326581 is 1856236091.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1897386481 + 8940100 = 43559^2 + 2990^2 .

It is a cyclic number.

It is not a de Polignac number, because 1906326581 - 2² = 1906326577 is a prime.

It is a super-2 number, since 2×1906326581² = 7268162066854299122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1906326589) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 953163290 + 953163291.

It is an arithmetic number, because the mean of its divisors is an integer number (953163291).

Almost surely, 2^1906326581 is an apocalyptic number.

It is an amenable number.

1906326581 is a deficient number, since it is larger than the sum of its proper divisors (1).

1906326581 is an equidigital number, since it uses as much as digits as its factorization.

1906326581 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 77760, while the sum is 41.

The square root of 1906326581 is about 43661.4999856853. The cubic root of 1906326581 is about 1239.9355197567.

The spelling of 1906326581 in words is "one billion, nine hundred six million, three hundred twenty-six thousand, five hundred eighty-one".