21675549 has 16 divisors (see below), whose sum is σ = 33182208. Its totient is φ = 12328752.

The previous prime is 21675529. The next prime is 21675553. The reversal of 21675549 is 94557612.

It is not a de Polignac number, because 21675549 - 2²⁰ = 20626973 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21675529) 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, 2494 + ... + 7040.

It is an arithmetic number, because the mean of its divisors is an integer number (2073888).

Almost surely, 2^21675549 is an apocalyptic number.

It is an amenable number.

21675549 is a deficient number, since it is larger than the sum of its proper divisors (11506659).

21675549 is a wasteful number, since it uses less digits than its factorization.

21675549 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4784.

The product of its digits is 75600, while the sum is 39.

The square root of 21675549 is about 4655.7006991429. The cubic root of 21675549 is about 278.8196442310.

The spelling of 21675549 in words is "twenty-one million, six hundred seventy-five thousand, five hundred forty-nine".