19780812 has 72 divisors (see below), whose sum is σ = 51979200. Its totient is φ = 6339168.

The previous prime is 19780781. The next prime is 19780837. The reversal of 19780812 is 21808791.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 142239 + ... + 142377.

Almost surely, 2^19780812 is an apocalyptic number.

19780812 is a gapful number since it is divisible by the number (12) 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 19780812, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25989600).

19780812 is an abundant number, since it is smaller than the sum of its proper divisors (32198388).

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

19780812 is a wasteful number, since it uses less digits than its factorization.

19780812 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 275 (or 270 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 36.

The square root of 19780812 is about 4447.5624784819. The cubic root of 19780812 is about 270.4465039994.

The spelling of 19780812 in words is "nineteen million, seven hundred eighty thousand, eight hundred twelve".