20519979 has 8 divisors (see below), whose sum is σ = 28549632. Its totient is φ = 13085160.

The previous prime is 20519977. The next prime is 20520029. The reversal of 20519979 is 97991502.

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

It is not a de Polignac number, because 20519979 - 2¹ = 20519977 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20519979.

It is not an unprimeable number, because it can be changed into a prime (20519977) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 148627 + ... + 148764.

It is an arithmetic number, because the mean of its divisors is an integer number (3568704).

Almost surely, 2^20519979 is an apocalyptic number.

20519979 is a deficient number, since it is larger than the sum of its proper divisors (8029653).

20519979 is a wasteful number, since it uses less digits than its factorization.

20519979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 297417.

The product of its (nonzero) digits is 51030, while the sum is 42.

The square root of 20519979 is about 4529.8983432302. The cubic root of 20519979 is about 273.7740647304.

The spelling of 20519979 in words is "twenty million, five hundred nineteen thousand, nine hundred seventy-nine".