21730838 has 4 divisors (see below), whose sum is σ = 32596260. Its totient is φ = 10865418.

The previous prime is 21730829. The next prime is 21730853. The reversal of 21730838 is 83803712.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5432708 + ... + 5432711.

It is an arithmetic number, because the mean of its divisors is an integer number (8149065).

Almost surely, 2^21730838 is an apocalyptic number.

21730838 is a deficient number, since it is larger than the sum of its proper divisors (10865422).

21730838 is a wasteful number, since it uses less digits than its factorization.

21730838 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10865421.

The product of its (nonzero) digits is 8064, while the sum is 32.

The square root of 21730838 is about 4661.6346918222. The cubic root of 21730838 is about 279.0565097527.

The spelling of 21730838 in words is "twenty-one million, seven hundred thirty thousand, eight hundred thirty-eight".