19987869 has 48 divisors (see below), whose sum is σ = 32175360. Its totient is φ = 10982400.

The previous prime is 19987861. The next prime is 19987879. The reversal of 19987869 is 96878991.

It is not a de Polignac number, because 19987869 - 2³ = 19987861 is a prime.

It is a super-2 number, since 2×19987869² = 799029814322322, which contains 22 as substring.

Its product of digits (1959552) is a multiple of the sum of its prime factors (162).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19987861) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 252972 + ... + 253050.

It is an arithmetic number, because the mean of its divisors is an integer number (670320).

Almost surely, 2^19987869 is an apocalyptic number.

It is an amenable number.

19987869 is a deficient number, since it is larger than the sum of its proper divisors (12187491).

19987869 is a wasteful number, since it uses less digits than its factorization.

19987869 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 162 (or 151 counting only the distinct ones).

The product of its digits is 1959552, while the sum is 57.

The square root of 19987869 is about 4470.7794622415. The cubic root of 19987869 is about 271.3868695595.

The spelling of 19987869 in words is "nineteen million, nine hundred eighty-seven thousand, eight hundred sixty-nine".