1000019981 has 2 divisors, whose sum is σ = 1000019982. Its totient is φ = 1000019980.

The previous prime is 1000019927. The next prime is 1000020001. The reversal of 1000019981 is 1899100001.

1000019981 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 511212100 + 488807881 = 22610^2 + 22109^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1000019981 is a prime.

It is a super-2 number, since 2×1000019981² = 2000079924798480722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1000019081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 500009990 + 500009991.

It is an arithmetic number, because the mean of its divisors is an integer number (500009991).

Almost surely, 2^1000019981 is an apocalyptic number.

It is an amenable number.

1000019981 is a deficient number, since it is larger than the sum of its proper divisors (1).

1000019981 is an equidigital number, since it uses as much as digits as its factorization.

1000019981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 648, while the sum is 29.

The square root of 1000019981 is about 31623.0925274553. The cubic root of 1000019981 is about 1000.0066602890.

Adding to 1000019981 its reverse (1899100001), we get a palindrome (2899119982).

The spelling of 1000019981 in words is "one billion, nineteen thousand, nine hundred eighty-one".