1787920649 has 2 divisors, whose sum is σ = 1787920650. Its totient is φ = 1787920648.

The previous prime is 1787920639. The next prime is 1787920657. The reversal of 1787920649 is 9460297871.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1661133049 + 126787600 = 40757^2 + 11260^2 .

It is a cyclic number.

It is not a de Polignac number, because 1787920649 - 2²⁴ = 1771143433 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1787920649.

It is not a weakly prime, because it can be changed into another prime (1787920639) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 893960324 + 893960325.

It is an arithmetic number, because the mean of its divisors is an integer number (893960325).

Almost surely, 2^1787920649 is an apocalyptic number.

It is an amenable number.

1787920649 is a deficient number, since it is larger than the sum of its proper divisors (1).

1787920649 is an equidigital number, since it uses as much as digits as its factorization.

1787920649 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1524096, while the sum is 53.

The square root of 1787920649 is about 42283.8107199434. The cubic root of 1787920649 is about 1213.7132134709.

The spelling of 1787920649 in words is "one billion, seven hundred eighty-seven million, nine hundred twenty thousand, six hundred forty-nine".