21675501 has 6 divisors (see below), whose sum is σ = 31309070. Its totient is φ = 14450328.

The previous prime is 21675491. The next prime is 21675529. The reversal of 21675501 is 10557612.

It can be written as a sum of positive squares in only one way, i.e., 21399876 + 275625 = 4626^2 + 525^2 .

It is not a de Polignac number, because 21675501 - 2¹³ = 21667309 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21675571) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1204186 + ... + 1204203.

Almost surely, 2^21675501 is an apocalyptic number.

It is an amenable number.

21675501 is a deficient number, since it is larger than the sum of its proper divisors (9633569).

21675501 is a wasteful number, since it uses less digits than its factorization.

21675501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2408395 (or 2408392 counting only the distinct ones).

The product of its (nonzero) digits is 2100, while the sum is 27.

The square root of 21675501 is about 4655.6955441695. The cubic root of 21675501 is about 278.8194384177.

The spelling of 21675501 in words is "twenty-one million, six hundred seventy-five thousand, five hundred one".