19639139 has 4 divisors (see below), whose sum is σ = 21149856. Its totient is φ = 18128424.

The previous prime is 19639121. The next prime is 19639157. The reversal of 19639139 is 93193691.

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

It is an interprime number because it is at equal distance from previous prime (19639121) and next prime (19639157).

It is a cyclic number.

It is not a de Polignac number, because 19639139 - 2²⁰ = 18590563 is a prime.

It is a super-2 number, since 2×19639139² = 771391561322642, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 19639096 and 19639105.

It is not an unprimeable number, because it can be changed into a prime (19639189) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 755339 + ... + 755364.

It is an arithmetic number, because the mean of its divisors is an integer number (5287464).

Almost surely, 2^19639139 is an apocalyptic number.

19639139 is a deficient number, since it is larger than the sum of its proper divisors (1510717).

19639139 is a wasteful number, since it uses less digits than its factorization.

19639139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1510716.

The product of its digits is 39366, while the sum is 41.

The square root of 19639139 is about 4431.6068192023. The cubic root of 19639139 is about 269.7992975770.

The spelling of 19639139 in words is "nineteen million, six hundred thirty-nine thousand, one hundred thirty-nine".