1628436581 has 2 divisors, whose sum is σ = 1628436582. Its totient is φ = 1628436580.

The previous prime is 1628436577. The next prime is 1628436611. The reversal of 1628436581 is 1856348261.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 815616481 + 812820100 = 28559^2 + 28510^2 .

It is a cyclic number.

It is not a de Polignac number, because 1628436581 - 2² = 1628436577 is a prime.

It is a super-2 number, since 2×1628436581² = 5303611396677939122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1628436571) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 814218290 + 814218291.

It is an arithmetic number, because the mean of its divisors is an integer number (814218291).

Almost surely, 2^1628436581 is an apocalyptic number.

It is an amenable number.

1628436581 is a deficient number, since it is larger than the sum of its proper divisors (1).

1628436581 is an equidigital number, since it uses as much as digits as its factorization.

1628436581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 276480, while the sum is 44.

The square root of 1628436581 is about 40353.8917701874. The cubic root of 1628436581 is about 1176.4955348854.

The spelling of 1628436581 in words is "one billion, six hundred twenty-eight million, four hundred thirty-six thousand, five hundred eighty-one".