1650781861 has 2 divisors, whose sum is σ = 1650781862. Its totient is φ = 1650781860.

The previous prime is 1650781849. The next prime is 1650781943. The reversal of 1650781861 is 1681870561.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1615557636 + 35224225 = 40194^2 + 5935^2 .

It is a cyclic number.

It is not a de Polignac number, because 1650781861 - 2¹⁹ = 1650257573 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1650781801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 825390930 + 825390931.

It is an arithmetic number, because the mean of its divisors is an integer number (825390931).

Almost surely, 2^1650781861 is an apocalyptic number.

It is an amenable number.

1650781861 is a deficient number, since it is larger than the sum of its proper divisors (1).

1650781861 is an equidigital number, since it uses as much as digits as its factorization.

1650781861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 80640, while the sum is 43.

The square root of 1650781861 is about 40629.8149269720. The cubic root of 1650781861 is about 1181.8523671286.

The spelling of 1650781861 in words is "one billion, six hundred fifty million, seven hundred eighty-one thousand, eight hundred sixty-one".