1780918649 has 2 divisors, whose sum is σ = 1780918650. Its totient is φ = 1780918648.

The previous prime is 1780918637. The next prime is 1780918661. The reversal of 1780918649 is 9468190871.

It is a balanced prime because it is at equal distance from previous prime (1780918637) and next prime (1780918661).

It can be written as a sum of positive squares in only one way, i.e., 1312975225 + 467943424 = 36235^2 + 21632^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1780918649 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1780918649.

It is not a weakly prime, because it can be changed into another prime (1780918619) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 890459324 + 890459325.

It is an arithmetic number, because the mean of its divisors is an integer number (890459325).

Almost surely, 2^1780918649 is an apocalyptic number.

It is an amenable number.

1780918649 is a deficient number, since it is larger than the sum of its proper divisors (1).

1780918649 is an equidigital number, since it uses as much as digits as its factorization.

1780918649 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 870912, while the sum is 53.

The square root of 1780918649 is about 42200.9318499011. The cubic root of 1780918649 is about 1212.1267265476.

The spelling of 1780918649 in words is "one billion, seven hundred eighty million, nine hundred eighteen thousand, six hundred forty-nine".