20421549 has 6 divisors (see below), whose sum is σ = 29497806. Its totient is φ = 13614360.

The previous prime is 20421503. The next prime is 20421553. The reversal of 20421549 is 94512402.

It can be written as a sum of positive squares in only one way, i.e., 12299049 + 8122500 = 3507^2 + 2850^2 .

It is not a de Polignac number, because 20421549 - 2¹¹ = 20419501 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20421449) 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, 1134522 + ... + 1134539.

It is an arithmetic number, because the mean of its divisors is an integer number (4916301).

Almost surely, 2^20421549 is an apocalyptic number.

It is an amenable number.

20421549 is a deficient number, since it is larger than the sum of its proper divisors (9076257).

20421549 is a wasteful number, since it uses less digits than its factorization.

20421549 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2269067 (or 2269064 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The square root of 20421549 is about 4519.0208010143. The cubic root of 20421549 is about 273.3356175036.

The spelling of 20421549 in words is "twenty million, four hundred twenty-one thousand, five hundred forty-nine".