21132549 has 8 divisors (see below), whose sum is σ = 31307520. Its totient is φ = 14088348.

The previous prime is 21132509. The next prime is 21132557. The reversal of 21132549 is 94523112.

21132549 is a `hidden beast` number, since 2 + 113 + 2 + 549 = 666.

It is not a de Polignac number, because 21132549 - 2¹³ = 21124357 is a prime.

It is a super-3 number, since 3×21132549³ (a number of 23 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 782687 = 21132549 / (2 + 1 + 1 + 3 + 2 + 5 + 4 + 9).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21132509) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 391317 + ... + 391370.

It is an arithmetic number, because the mean of its divisors is an integer number (3913440).

Almost surely, 2^21132549 is an apocalyptic number.

It is an amenable number.

21132549 is a deficient number, since it is larger than the sum of its proper divisors (10174971).

21132549 is an equidigital number, since it uses as much as digits as its factorization.

21132549 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 782696 (or 782690 counting only the distinct ones).

The product of its digits is 2160, while the sum is 27.

The square root of 21132549 is about 4597.0152272969. The cubic root of 21132549 is about 276.4716651420.

The spelling of 21132549 in words is "twenty-one million, one hundred thirty-two thousand, five hundred forty-nine".