19949978 has 8 divisors (see below), whose sum is σ = 29966772. Its totient is φ = 9961056.

The previous prime is 19949977. The next prime is 19950013. The reversal of 19949978 is 87994991.

It can be written as a sum of positive squares in 2 ways, for example, as 19598329 + 351649 = 4427^2 + 593^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (19949977) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5075 + ... + 8102.

Almost surely, 2^19949978 is an apocalyptic number.

19949978 is a deficient number, since it is larger than the sum of its proper divisors (10016794).

19949978 is a wasteful number, since it uses less digits than its factorization.

19949978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13936.

The product of its digits is 1469664, while the sum is 56.

The square root of 19949978 is about 4466.5398240696. The cubic root of 19949978 is about 271.2152717331.

The spelling of 19949978 in words is "nineteen million, nine hundred forty-nine thousand, nine hundred seventy-eight".