1650169981 has 2 divisors, whose sum is σ = 1650169982. Its totient is φ = 1650169980.

The previous prime is 1650169979. The next prime is 1650170023. The reversal of 1650169981 is 1899610561.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1177107481 + 473062500 = 34309^2 + 21750^2 .

It is an emirp because it is prime and its reverse (1899610561) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1650169981 - 2¹ = 1650169979 is a prime.

It is a super-5 number, since 5×1650169981⁵ (a number of 47 digits) contains 55555 as substring. Note that it is a super-d number also for d = 2.

Together with 1650169979, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1650169921) 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, 825084990 + 825084991.

It is an arithmetic number, because the mean of its divisors is an integer number (825084991).

Almost surely, 2^1650169981 is an apocalyptic number.

It is an amenable number.

1650169981 is a deficient number, since it is larger than the sum of its proper divisors (1).

1650169981 is an equidigital number, since it uses as much as digits as its factorization.

1650169981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 116640, while the sum is 46.

The square root of 1650169981 is about 40622.2842907683. The cubic root of 1650169981 is about 1181.7063269986.

The spelling of 1650169981 in words is "one billion, six hundred fifty million, one hundred sixty-nine thousand, nine hundred eighty-one".