19720538 has 8 divisors (see below), whose sum is σ = 29603988. Its totient is φ = 9852544.

The previous prime is 19720523. The next prime is 19720543. The reversal of 19720538 is 83502791.

It can be written as a sum of positive squares in 2 ways, for example, as 19562929 + 157609 = 4423^2 + 397^2 .

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 = 19720498 and 19720507.

It is an unprimeable number.

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 in 3 ways as a sum of consecutive naturals, for example, 170 + ... + 6282.

Almost surely, 2^19720538 is an apocalyptic number.

19720538 is a deficient number, since it is larger than the sum of its proper divisors (9883450).

19720538 is a wasteful number, since it uses less digits than its factorization.

19720538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7728.

The product of its (nonzero) digits is 15120, while the sum is 35.

The square root of 19720538 is about 4440.7812375752. The cubic root of 19720538 is about 270.1715325194.

The spelling of 19720538 in words is "nineteen million, seven hundred twenty thousand, five hundred thirty-eight".