19781073 has 12 divisors (see below), whose sum is σ = 30770740. Its totient is φ = 12172896.

The previous prime is 19781053. The next prime is 19781077. The reversal of 19781073 is 37018791.

It can be written as a sum of positive squares in 2 ways, for example, as 4359744 + 15421329 = 2088^2 + 3927^2 .

It is not a de Polignac number, because 19781073 - 2¹³ = 19772881 is a prime.

It is not an unprimeable number, because it can be changed into a prime (19781077) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 84418 + ... + 84651.

Almost surely, 2^19781073 is an apocalyptic number.

19781073 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

It is an amenable number.

19781073 is a deficient number, since it is larger than the sum of its proper divisors (10989667).

19781073 is a wasteful number, since it uses less digits than its factorization.

19781073 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169088 (or 169085 counting only the distinct ones).

The product of its (nonzero) digits is 10584, while the sum is 36.

The square root of 19781073 is about 4447.5918203001. The cubic root of 19781073 is about 270.4476934724.

The spelling of 19781073 in words is "nineteen million, seven hundred eighty-one thousand, seventy-three".