19720978 has 8 divisors (see below), whose sum is σ = 29648700. Its totient is φ = 9838080.

The previous prime is 19720949. The next prime is 19720997. The reversal of 19720978 is 87902791.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 18861649 + 859329 = 4343^2 + 927^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10083 + ... + 11878.

Almost surely, 2^19720978 is an apocalyptic number.

19720978 is a deficient number, since it is larger than the sum of its proper divisors (9927722).

19720978 is a wasteful number, since it uses less digits than its factorization.

19720978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22412.

The product of its (nonzero) digits is 63504, while the sum is 43.

The square root of 19720978 is about 4440.8307781315. The cubic root of 19720978 is about 270.1735418390.

The spelling of 19720978 in words is "nineteen million, seven hundred twenty thousand, nine hundred seventy-eight".