21254389 has 4 divisors (see below), whose sum is σ = 22889356. Its totient is φ = 19619424.

The previous prime is 21254383. The next prime is 21254393. The reversal of 21254389 is 98345212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1380625 + 19873764 = 1175^2 + 4458^2 .

It is a cyclic number.

It is not a de Polignac number, because 21254389 - 2³ = 21254381 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21254381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 817464 + ... + 817489.

It is an arithmetic number, because the mean of its divisors is an integer number (5722339).

Almost surely, 2^21254389 is an apocalyptic number.

It is an amenable number.

21254389 is a deficient number, since it is larger than the sum of its proper divisors (1634967).

21254389 is a wasteful number, since it uses less digits than its factorization.

21254389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1634966.

The product of its digits is 17280, while the sum is 34.

The square root of 21254389 is about 4610.2482579575. The cubic root of 21254389 is about 277.0019809839.

The spelling of 21254389 in words is "twenty-one million, two hundred fifty-four thousand, three hundred eighty-nine".