19720738 has 8 divisors (see below), whose sum is σ = 29688732. Its totient is φ = 9824496.

The previous prime is 19720733. The next prime is 19720781. The reversal of 19720738 is 83702791.

It can be written as a sum of positive squares in 2 ways, for example, as 16703569 + 3017169 = 4087^2 + 1737^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 19720697 and 19720706.

It is not an unprimeable number, because it can be changed into a prime (19720733) 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, 17245 + ... + 18352.

Almost surely, 2^19720738 is an apocalyptic number.

19720738 is a deficient number, since it is larger than the sum of its proper divisors (9967994).

19720738 is a wasteful number, since it uses less digits than its factorization.

19720738 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35876.

The product of its (nonzero) digits is 21168, while the sum is 37.

The square root of 19720738 is about 4440.8037560784. The cubic root of 19720738 is about 270.1724458502.

The spelling of 19720738 in words is "nineteen million, seven hundred twenty thousand, seven hundred thirty-eight".