21675563 has 16 divisors (see below), whose sum is σ = 26798016. Its totient is φ = 17072640.

The previous prime is 21675559. The next prime is 21675571. The reversal of 21675563 is 36557612.

It is not a de Polignac number, because 21675563 - 2² = 21675559 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21675553) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28103 + ... + 28863.

It is an arithmetic number, because the mean of its divisors is an integer number (1674876).

Almost surely, 2^21675563 is an apocalyptic number.

21675563 is a deficient number, since it is larger than the sum of its proper divisors (5122453).

21675563 is a wasteful number, since it uses less digits than its factorization.

21675563 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1094.

The product of its digits is 37800, while the sum is 35.

The square root of 21675563 is about 4655.7022026758. The cubic root of 21675563 is about 278.8197042599.

It can be divided in two parts, 2167 and 5563, that multiplied together give a palindrome (12055021).

The spelling of 21675563 in words is "twenty-one million, six hundred seventy-five thousand, five hundred sixty-three".