1641378649 has 2 divisors, whose sum is σ = 1641378650. Its totient is φ = 1641378648.

The previous prime is 1641378623. The next prime is 1641378653. The reversal of 1641378649 is 9468731461.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1601600400 + 39778249 = 40020^2 + 6307^2 .

It is a cyclic number.

It is not a de Polignac number, because 1641378649 - 2⁷ = 1641378521 is a prime.

It is not a weakly prime, because it can be changed into another prime (1641378619) 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, 820689324 + 820689325.

It is an arithmetic number, because the mean of its divisors is an integer number (820689325).

Almost surely, 2^1641378649 is an apocalyptic number.

It is an amenable number.

1641378649 is a deficient number, since it is larger than the sum of its proper divisors (1).

1641378649 is an equidigital number, since it uses as much as digits as its factorization.

1641378649 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 870912, while the sum is 49.

The square root of 1641378649 is about 40513.9315421251. The cubic root of 1641378649 is about 1179.6040635142.

The spelling of 1641378649 in words is "one billion, six hundred forty-one million, three hundred seventy-eight thousand, six hundred forty-nine".