1987556801 has 2 divisors, whose sum is σ = 1987556802. Its totient is φ = 1987556800.

The previous prime is 1987556699. The next prime is 1987556849. The reversal of 1987556801 is 1086557891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1154368576 + 833188225 = 33976^2 + 28865^2 .

It is a cyclic number.

It is not a de Polignac number, because 1987556801 - 2¹⁸ = 1987294657 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1987556801.

It is not a weakly prime, because it can be changed into another prime (1987556401) 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, 993778400 + 993778401.

It is an arithmetic number, because the mean of its divisors is an integer number (993778401).

Almost surely, 2^1987556801 is an apocalyptic number.

It is an amenable number.

1987556801 is a deficient number, since it is larger than the sum of its proper divisors (1).

1987556801 is an equidigital number, since it uses as much as digits as its factorization.

1987556801 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 604800, while the sum is 50.

The square root of 1987556801 is about 44582.0232941485. The cubic root of 1987556801 is about 1257.3027042065.

The spelling of 1987556801 in words is "one billion, nine hundred eighty-seven million, five hundred fifty-six thousand, eight hundred one".