1505643661 has 2 divisors, whose sum is σ = 1505643662. Its totient is φ = 1505643660.

The previous prime is 1505643611. The next prime is 1505643673. The reversal of 1505643661 is 1663465051.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 925315561 + 580328100 = 30419^2 + 24090^2 .

It is a cyclic number.

It is not a de Polignac number, because 1505643661 - 2¹⁹ = 1505119373 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1505643661.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1505643611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 752821830 + 752821831.

It is an arithmetic number, because the mean of its divisors is an integer number (752821831).

Almost surely, 2^1505643661 is an apocalyptic number.

It is an amenable number.

1505643661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1505643661 is an equidigital number, since it uses as much as digits as its factorization.

1505643661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 64800, while the sum is 37.

The square root of 1505643661 is about 38802.6244086660. The cubic root of 1505643661 is about 1146.1480856102.

The spelling of 1505643661 in words is "one billion, five hundred five million, six hundred forty-three thousand, six hundred sixty-one".