1551221663 has 2 divisors, whose sum is σ = 1551221664. Its totient is φ = 1551221662.

The previous prime is 1551221599. The next prime is 1551221671. The reversal of 1551221663 is 3661221551.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1551221663 - 2⁶ = 1551221599 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1551221563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 775610831 + 775610832.

It is an arithmetic number, because the mean of its divisors is an integer number (775610832).

Almost surely, 2^1551221663 is an apocalyptic number.

1551221663 is a deficient number, since it is larger than the sum of its proper divisors (1).

1551221663 is an equidigital number, since it uses as much as digits as its factorization.

1551221663 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10800, while the sum is 32.

The square root of 1551221663 is about 39385.5514497385. The cubic root of 1551221663 is about 1157.5984955688.

The spelling of 1551221663 in words is "one billion, five hundred fifty-one million, two hundred twenty-one thousand, six hundred sixty-three".