21556465 has 16 divisors (see below), whose sum is σ = 29652480. Its totient is φ = 14736960.

The previous prime is 21556441. The next prime is 21556477. The reversal of 21556465 is 56465512.

It is not a de Polignac number, because 21556465 - 2¹³ = 21548273 is a prime.

21556465 is a modest number, since divided by 6465 gives 2155 as remainder.

It is a self number, because there is not a number n which added to its sum of digits gives 21556465.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14371 + ... + 15799.

It is an arithmetic number, because the mean of its divisors is an integer number (1853280).

Almost surely, 2^21556465 is an apocalyptic number.

It is an amenable number.

21556465 is a deficient number, since it is larger than the sum of its proper divisors (8096015).

21556465 is a wasteful number, since it uses less digits than its factorization.

21556465 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1872.

The product of its digits is 36000, while the sum is 34.

The square root of 21556465 is about 4642.8940328205. The cubic root of 21556465 is about 278.3081008676.

The spelling of 21556465 in words is "twenty-one million, five hundred fifty-six thousand, four hundred sixty-five".