19779456 has 64 divisors (see below), whose sum is σ = 55324800. Its totient is φ = 6243840.

The previous prime is 19779451. The next prime is 19779493. The reversal of 19779456 is 65497791.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (64).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19779451) 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, 5941 + ... + 8651.

It is an arithmetic number, because the mean of its divisors is an integer number (864450).

Almost surely, 2^19779456 is an apocalyptic number.

19779456 is a gapful number since it is divisible by the number (16) 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 19779456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27662400).

19779456 is an abundant number, since it is smaller than the sum of its proper divisors (35545344).

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

19779456 is a wasteful number, since it uses less digits than its factorization.

19779456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2747 (or 2735 counting only the distinct ones).

The product of its digits is 476280, while the sum is 48.

The square root of 19779456 is about 4447.4100328169. The cubic root of 19779456 is about 270.4403240401.

The spelling of 19779456 in words is "nineteen million, seven hundred seventy-nine thousand, four hundred fifty-six".