1551661603 has 2 divisors, whose sum is σ = 1551661604. Its totient is φ = 1551661602.

The previous prime is 1551661547. The next prime is 1551661651. The reversal of 1551661603 is 3061661551.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1551661603 - 2⁹ = 1551661091 is a prime.

It is not a weakly prime, because it can be changed into another prime (1551661663) 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, 775830801 + 775830802.

It is an arithmetic number, because the mean of its divisors is an integer number (775830802).

Almost surely, 2^1551661603 is an apocalyptic number.

1551661603 is a deficient number, since it is larger than the sum of its proper divisors (1).

1551661603 is an equidigital number, since it uses as much as digits as its factorization.

1551661603 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16200, while the sum is 34.

The square root of 1551661603 is about 39391.1360968429. The cubic root of 1551661603 is about 1157.7079202365.

The spelling of 1551661603 in words is "one billion, five hundred fifty-one million, six hundred sixty-one thousand, six hundred three".