21536501 has 16 divisors (see below), whose sum is σ = 26438400. Its totient is φ = 17122560.

The previous prime is 21536491. The next prime is 21536503. The reversal of 21536501 is 10563512.

It is not a de Polignac number, because 21536501 - 2¹⁰ = 21535477 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21536503) 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, 7175 + ... + 9723.

It is an arithmetic number, because the mean of its divisors is an integer number (1652400).

Almost surely, 2^21536501 is an apocalyptic number.

It is an amenable number.

21536501 is a deficient number, since it is larger than the sum of its proper divisors (4901899).

21536501 is a wasteful number, since it uses less digits than its factorization.

21536501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2644.

The product of its (nonzero) digits is 900, while the sum is 23.

The square root of 21536501 is about 4640.7435826600. The cubic root of 21536501 is about 278.2221582198. Note that the first 3 decimals are identical.

The spelling of 21536501 in words is "twenty-one million, five hundred thirty-six thousand, five hundred one".