21505414 has 64 divisors (see below), whose sum is σ = 41472000. Its totient is φ = 8330784.

The previous prime is 21505381. The next prime is 21505417. The reversal of 21505414 is 41450512.

It is a super-2 number, since 2×21505414² = 924965662622792, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21505417) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 457539 + ... + 457585.

It is an arithmetic number, because the mean of its divisors is an integer number (648000).

Almost surely, 2^21505414 is an apocalyptic number.

21505414 is a deficient number, since it is larger than the sum of its proper divisors (19966586).

21505414 is a wasteful number, since it uses less digits than its factorization.

21505414 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 122 (or 108 counting only the distinct ones).

The product of its (nonzero) digits is 800, while the sum is 22.

The square root of 21505414 is about 4637.3930176339. The cubic root of 21505414 is about 278.0882265735.

Adding to 21505414 its reverse (41450512), we get a palindrome (62955926).

The spelling of 21505414 in words is "twenty-one million, five hundred five thousand, four hundred fourteen".