21240938 has 8 divisors (see below), whose sum is σ = 31886688. Its totient is φ = 10612044.

The previous prime is 21240913. The next prime is 21240971. The reversal of 21240938 is 83904212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21240938.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 356 + ... + 6527.

It is an arithmetic number, because the mean of its divisors is an integer number (3985836).

Almost surely, 2^21240938 is an apocalyptic number.

21240938 is a deficient number, since it is larger than the sum of its proper divisors (10645750).

21240938 is a wasteful number, since it uses less digits than its factorization.

21240938 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8428.

The product of its (nonzero) digits is 3456, while the sum is 29.

The square root of 21240938 is about 4608.7892119297. The cubic root of 21240938 is about 276.9435343901.

The spelling of 21240938 in words is "twenty-one million, two hundred forty thousand, nine hundred thirty-eight".