21919838 has 4 divisors (see below), whose sum is σ = 32879760. Its totient is φ = 10959918.

The previous prime is 21919831. The next prime is 21919847. The reversal of 21919838 is 83891912.

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

It is a junction number, because it is equal to n+sod(n) for n = 21919795 and 21919804.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21919831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5479958 + ... + 5479961.

It is an arithmetic number, because the mean of its divisors is an integer number (8219940).

Almost surely, 2^21919838 is an apocalyptic number.

21919838 is a deficient number, since it is larger than the sum of its proper divisors (10959922).

21919838 is a wasteful number, since it uses less digits than its factorization.

21919838 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10959921.

The product of its digits is 31104, while the sum is 41.

The square root of 21919838 is about 4681.8626635133. The cubic root of 21919838 is about 279.8631899672.

The spelling of 21919838 in words is "twenty-one million, nine hundred nineteen thousand, eight hundred thirty-eight".