21523603 has 8 divisors (see below), whose sum is σ = 22577472. Its totient is φ = 20494656.

The previous prime is 21523591. The next prime is 21523609. The reversal of 21523603 is 30632512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21523603 - 2⁵ = 21523571 is a prime.

It is a super-2 number, since 2×21523603² = 926530972203218, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21523609) 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 in 7 ways as a sum of consecutive naturals, for example, 4450 + ... + 7927.

It is an arithmetic number, because the mean of its divisors is an integer number (2822184).

Almost surely, 2^21523603 is an apocalyptic number.

21523603 is a deficient number, since it is larger than the sum of its proper divisors (1053869).

21523603 is a wasteful number, since it uses less digits than its factorization.

21523603 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12461.

The product of its (nonzero) digits is 1080, while the sum is 22.

The square root of 21523603 is about 4639.3537265442. The cubic root of 21523603 is about 278.1666056177.

The spelling of 21523603 in words is "twenty-one million, five hundred twenty-three thousand, six hundred three".