21508334 has 4 divisors (see below), whose sum is σ = 32262504. Its totient is φ = 10754166.

The previous prime is 21508321. The next prime is 21508337. The reversal of 21508334 is 43380512.

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

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21508337) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5377082 + ... + 5377085.

It is an arithmetic number, because the mean of its divisors is an integer number (8065626).

Almost surely, 2^21508334 is an apocalyptic number.

21508334 is a deficient number, since it is larger than the sum of its proper divisors (10754170).

21508334 is a wasteful number, since it uses less digits than its factorization.

21508334 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10754169.

The product of its (nonzero) digits is 2880, while the sum is 26.

The square root of 21508334 is about 4637.7078390084. The cubic root of 21508334 is about 278.1008122550.

Adding to 21508334 its reverse (43380512), we get a palindrome (64888846).

The spelling of 21508334 in words is "twenty-one million, five hundred eight thousand, three hundred thirty-four".