21849549 has 16 divisors (see below), whose sum is σ = 29621760. Its totient is φ = 14324400.

The previous prime is 21849523. The next prime is 21849551. The reversal of 21849549 is 94594812.

It is not a de Polignac number, because 21849549 - 2¹³ = 21841357 is a prime.

Its product of digits (103680) is a multiple of the sum of its prime divisors (640).

It is a self number, because there is not a number n which added to its sum of digits gives 21849549.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21849559) 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, 62794 + ... + 63140.

It is an arithmetic number, because the mean of its divisors is an integer number (1851360).

Almost surely, 2^21849549 is an apocalyptic number.

It is an amenable number.

21849549 is a deficient number, since it is larger than the sum of its proper divisors (7772211).

21849549 is a wasteful number, since it uses less digits than its factorization.

21849549 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 640.

The product of its digits is 103680, while the sum is 42.

The square root of 21849549 is about 4674.3501152567. The cubic root of 21849549 is about 279.5637296100.

The spelling of 21849549 in words is "twenty-one million, eight hundred forty-nine thousand, five hundred forty-nine".