19979946 has 72 divisors (see below), whose sum is σ = 52284960. Its totient is φ = 5701752.

The previous prime is 19979941. The next prime is 19979959. The reversal of 19979946 is 64997991.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 19979892 and 19979901.

It is not an unprimeable number, because it can be changed into a prime (19979941) by changing a digit.

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 35 ways as a sum of consecutive naturals, for example, 23395 + ... + 24233.

It is an arithmetic number, because the mean of its divisors is an integer number (726180).

Almost surely, 2^19979946 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19979946, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26142480).

19979946 is an abundant number, since it is smaller than the sum of its proper divisors (32305014).

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

19979946 is an equidigital number, since it uses as much as digits as its factorization.

19979946 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 870 (or 851 counting only the distinct ones).

The product of its digits is 1102248, while the sum is 54.

The square root of 19979946 is about 4469.8932873168. The cubic root of 19979946 is about 271.3510064345.

The spelling of 19979946 in words is "nineteen million, nine hundred seventy-nine thousand, nine hundred forty-six".