19779144 has 144 divisors (see below), whose sum is σ = 63680400. Its totient is φ = 5100480.

The previous prime is 19779139. The next prime is 19779157. The reversal of 19779144 is 44197791.

It is a Harshad number since it is a multiple of its sum of digits (42).

Its product of digits (63504) is a multiple of the sum of its prime divisors (162).

It is a junction number, because it is equal to n+sod(n) for n = 19779096 and 19779105.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 142227 + ... + 142365.

It is an arithmetic number, because the mean of its divisors is an integer number (442225).

Almost surely, 2^19779144 is an apocalyptic number.

19779144 is a gapful number since it is divisible by the number (14) 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 19779144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31840200).

19779144 is an abundant number, since it is smaller than the sum of its proper divisors (43901256).

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

19779144 is a wasteful number, since it uses less digits than its factorization.

19779144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 184 (or 162 counting only the distinct ones).

The product of its digits is 63504, while the sum is 42.

The square root of 19779144 is about 4447.3749560836. The cubic root of 19779144 is about 270.4389020626.

The spelling of 19779144 in words is "nineteen million, seven hundred seventy-nine thousand, one hundred forty-four".