19981278 has 24 divisors (see below), whose sum is σ = 43506216. Its totient is φ = 6627600.

The previous prime is 19981249. The next prime is 19981289. The reversal of 19981278 is 87218991.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1168 + ... + 6428.

It is an arithmetic number, because the mean of its divisors is an integer number (1812759).

Almost surely, 2^19981278 is an apocalyptic number.

19981278 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

19981278 is an abundant number, since it is smaller than the sum of its proper divisors (23524938).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

19981278 is a wasteful number, since it uses less digits than its factorization.

19981278 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5480 (or 5477 counting only the distinct ones).

The product of its digits is 72576, while the sum is 45.

The square root of 19981278 is about 4470.0422816792. The cubic root of 19981278 is about 271.3570363392.

The spelling of 19981278 in words is "nineteen million, nine hundred eighty-one thousand, two hundred seventy-eight".