21605414 has 4 divisors (see below), whose sum is σ = 32408124. Its totient is φ = 10802706.

The previous prime is 21605411. The next prime is 21605417. The reversal of 21605414 is 41450612.

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

It is an interprime number because it is at equal distance from previous prime (21605411) and next prime (21605417).

It is a super-2 number, since 2×21605414² = 933587828222792, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21605414.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21605411) 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, 5401352 + ... + 5401355.

It is an arithmetic number, because the mean of its divisors is an integer number (8102031).

Almost surely, 2^21605414 is an apocalyptic number.

21605414 is a deficient number, since it is larger than the sum of its proper divisors (10802710).

21605414 is a wasteful number, since it uses less digits than its factorization.

21605414 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10802709.

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 21605414 is about 4648.1624326179. The cubic root of 21605414 is about 278.5185961859.

The spelling of 21605414 in words is "twenty-one million, six hundred five thousand, four hundred fourteen".