1006919981 has 2 divisors, whose sum is σ = 1006919982. Its totient is φ = 1006919980.

The previous prime is 1006919957. The next prime is 1006919983. The reversal of 1006919981 is 1899196001.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 981255625 + 25664356 = 31325^2 + 5066^2 .

It is an emirp because it is prime and its reverse (1899196001) is a distict prime. It is also a bemirp because it and its reverse can be mirrored producing other two distinct primes, 1866169001 and 1009616681.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1006919981 is a prime.

It is a super-2 number, since 2×1006919981² = 2027775696274080722, which contains 22 as substring.

Together with 1006919983, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1006919983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 503459990 + 503459991.

It is an arithmetic number, because the mean of its divisors is an integer number (503459991).

Almost surely, 2^1006919981 is an apocalyptic number.

It is an amenable number.

1006919981 is a deficient number, since it is larger than the sum of its proper divisors (1).

1006919981 is an equidigital number, since it uses as much as digits as its factorization.

1006919981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34992, while the sum is 44.

The square root of 1006919981 is about 31732.0024738433. The cubic root of 1006919981 is about 1002.3013600126.

The spelling of 1006919981 in words is "one billion, six million, nine hundred nineteen thousand, nine hundred eighty-one".