1001549981 has 2 divisors, whose sum is σ = 1001549982. Its totient is φ = 1001549980.

The previous prime is 1001549977. The next prime is 1001549993. The reversal of 1001549981 is 1899451001.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 828864100 + 172685881 = 28790^2 + 13141^2 .

It is a cyclic number.

It is not a de Polignac number, because 1001549981 - 2² = 1001549977 is a prime.

It is a super-2 number, since 2×1001549981² = 2006204728882200722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1001549921) 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, 500774990 + 500774991.

It is an arithmetic number, because the mean of its divisors is an integer number (500774991).

Almost surely, 2^1001549981 is an apocalyptic number.

It is an amenable number.

1001549981 is a deficient number, since it is larger than the sum of its proper divisors (1).

1001549981 is an equidigital number, since it uses as much as digits as its factorization.

1001549981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12960, while the sum is 38.

The square root of 1001549981 is about 31647.2744640040. The cubic root of 1001549981 is about 1000.5163936251.

The spelling of 1001549981 in words is "one billion, one million, five hundred forty-nine thousand, nine hundred eighty-one".