1631503981 has 2 divisors, whose sum is σ = 1631503982. Its totient is φ = 1631503980.

The previous prime is 1631503961. The next prime is 1631504003. The reversal of 1631503981 is 1893051361.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1438988356 + 192515625 = 37934^2 + 13875^2 .

It is an emirp because it is prime and its reverse (1893051361) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1631503981 - 2⁵ = 1631503949 is a prime.

It is a super-2 number, since 2×1631503981² = 5323610480037696722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1631503981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1631503901) 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, 815751990 + 815751991.

It is an arithmetic number, because the mean of its divisors is an integer number (815751991).

Almost surely, 2^1631503981 is an apocalyptic number.

It is an amenable number.

1631503981 is a deficient number, since it is larger than the sum of its proper divisors (1).

1631503981 is an equidigital number, since it uses as much as digits as its factorization.

1631503981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 19440, while the sum is 37.

The square root of 1631503981 is about 40391.8801369780. The cubic root of 1631503981 is about 1177.2337723914.

The spelling of 1631503981 in words is "one billion, six hundred thirty-one million, five hundred three thousand, nine hundred eighty-one".