20213549 has 4 divisors (see below), whose sum is σ = 21277440. Its totient is φ = 19149660.

The previous prime is 20213503. The next prime is 20213563. The reversal of 20213549 is 94531202.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20213549 - 2⁸ = 20213293 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 (20213749) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 531917 + ... + 531954.

It is an arithmetic number, because the mean of its divisors is an integer number (5319360).

Almost surely, 2^20213549 is an apocalyptic number.

It is an amenable number.

20213549 is a deficient number, since it is larger than the sum of its proper divisors (1063891).

20213549 is a wasteful number, since it uses less digits than its factorization.

20213549 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1063890.

The product of its (nonzero) digits is 2160, while the sum is 26.

The square root of 20213549 is about 4495.9480646467. The cubic root of 20213549 is about 272.4044453566.

The spelling of 20213549 in words is "twenty million, two hundred thirteen thousand, five hundred forty-nine".