19879820 has 36 divisors (see below), whose sum is σ = 43664880. Its totient is φ = 7602144.

The previous prime is 19879813. The next prime is 19879879. The reversal of 19879820 is 2897891.

It is a Smith number, since the sum of its digits (44) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9641 + ... + 11519.

Almost surely, 2^19879820 is an apocalyptic number.

19879820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19879820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21832440).

19879820 is an abundant number, since it is smaller than the sum of its proper divisors (23785060).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

19879820 is a wasteful number, since it uses less digits than its factorization.

19879820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1934 (or 1909 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 44.

The square root of 19879820 is about 4458.6791766172. The cubic root of 19879820 is about 270.8969711339.

The spelling of 19879820 in words is "nineteen million, eight hundred seventy-nine thousand, eight hundred twenty".