21869838 has 20 divisors (see below), whose sum is σ = 49005000. Its totient is φ = 7289892.

The previous prime is 21869821. The next prime is 21869839. The reversal of 21869838 is 83896812.

It is a junction number, because it is equal to n+sod(n) for n = 21869793 and 21869802.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21869839) 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 9 ways as a sum of consecutive naturals, for example, 67338 + ... + 67661.

It is an arithmetic number, because the mean of its divisors is an integer number (2450250).

Almost surely, 2^21869838 is an apocalyptic number.

21869838 is an abundant number, since it is smaller than the sum of its proper divisors (27135162).

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

21869838 is a wasteful number, since it uses less digits than its factorization.

21869838 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135013 (or 135004 counting only the distinct ones).

The product of its digits is 165888, while the sum is 45.

The square root of 21869838 is about 4676.5198598958. The cubic root of 21869838 is about 279.6502350380.

The spelling of 21869838 in words is "twenty-one million, eight hundred sixty-nine thousand, eight hundred thirty-eight".