1909909979 has 2 divisors, whose sum is σ = 1909909980. Its totient is φ = 1909909978.

The previous prime is 1909909913. The next prime is 1909909997. The reversal of 1909909979 is 9799099091.

It is a happy number.

Together with next prime (1909909997) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1909909979 is a prime.

It is a super-2 number, since 2×1909909979² = 7295512255767560882, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1909909879) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 954954989 + 954954990.

It is an arithmetic number, because the mean of its divisors is an integer number (954954990).

Almost surely, 2^1909909979 is an apocalyptic number.

1909909979 is a deficient number, since it is larger than the sum of its proper divisors (1).

1909909979 is an equidigital number, since it uses as much as digits as its factorization.

1909909979 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3720087, while the sum is 62.

The square root of 1909909979 is about 43702.5168497193. The cubic root of 1909909979 is about 1240.7119521897.

The spelling of 1909909979 in words is "one billion, nine hundred nine million, nine hundred nine thousand, nine hundred seventy-nine".