19978979 has 2 divisors, whose sum is σ = 19978980. Its totient is φ = 19978978.

The previous prime is 19978967. The next prime is 19978991. The reversal of 19978979 is 97987991.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (19978967) and next prime (19978991).

It is a cyclic number.

It is not a de Polignac number, because 19978979 - 2¹² = 19974883 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (19978919) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9989489 + 9989490.

It is an arithmetic number, because the mean of its divisors is an integer number (9989490).

Almost surely, 2^19978979 is an apocalyptic number.

19978979 is a deficient number, since it is larger than the sum of its proper divisors (1).

19978979 is an equidigital number, since it uses as much as digits as its factorization.

19978979 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2571912, while the sum is 59.

The square root of 19978979 is about 4469.7851178776. The cubic root of 19978979 is about 271.3466287007.

The spelling of 19978979 in words is "nineteen million, nine hundred seventy-eight thousand, nine hundred seventy-nine".