19880639 has 4 divisors (see below), whose sum is σ = 20160720. Its totient is φ = 19600560.

The previous prime is 19880629. The next prime is 19880647. The reversal of 19880639 is 93608891.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 19880639 - 2⁸ = 19880383 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 19880639.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19880629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 139934 + ... + 140075.

It is an arithmetic number, because the mean of its divisors is an integer number (5040180).

Almost surely, 2^19880639 is an apocalyptic number.

19880639 is a deficient number, since it is larger than the sum of its proper divisors (280081).

19880639 is an equidigital number, since it uses as much as digits as its factorization.

19880639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 280080.

The product of its (nonzero) digits is 93312, while the sum is 44.

The square root of 19880639 is about 4458.7710190141. The cubic root of 19880639 is about 270.9006911806.

It can be divided in two parts, 19880 and 639, that multiplied together give a triangular number (12703320 = T₅₀₄₀).

The spelling of 19880639 in words is "nineteen million, eight hundred eighty thousand, six hundred thirty-nine".