19979505 has 144 divisors (see below), whose sum is σ = 47056464. Its totient is φ = 7741440.

The previous prime is 19979503. The next prime is 19979527. The reversal of 19979505 is 50597991.

It can be written as a sum of positive squares in 8 ways, for example, as 3038049 + 16941456 = 1743^2 + 4116^2 .

It is not a de Polignac number, because 19979505 - 2¹ = 19979503 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (19979503) 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 143 ways as a sum of consecutive naturals, for example, 487285 + ... + 487325.

It is an arithmetic number, because the mean of its divisors is an integer number (326781).

Almost surely, 2^19979505 is an apocalyptic number.

19979505 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

19979505 is an abundant number, since it is smaller than the sum of its proper divisors (27076959).

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

19979505 is a wasteful number, since it uses less digits than its factorization.

19979505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96 (or 86 counting only the distinct ones).

The product of its (nonzero) digits is 127575, while the sum is 45.

The square root of 19979505 is about 4469.8439570079. The cubic root of 19979505 is about 271.3490099881.

The spelling of 19979505 in words is "nineteen million, nine hundred seventy-nine thousand, five hundred five".