21754609 has 2 divisors, whose sum is σ = 21754610. Its totient is φ = 21754608.

The previous prime is 21754597. The next prime is 21754627. The reversal of 21754609 is 90645712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21594609 + 160000 = 4647^2 + 400^2 .

It is a cyclic number.

It is not a de Polignac number, because 21754609 - 2⁹ = 21754097 is a prime.

It is not a weakly prime, because it can be changed into another prime (21752609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10877304 + 10877305.

It is an arithmetic number, because the mean of its divisors is an integer number (10877305).

Almost surely, 2^21754609 is an apocalyptic number.

It is an amenable number.

21754609 is a deficient number, since it is larger than the sum of its proper divisors (1).

21754609 is an equidigital number, since it uses as much as digits as its factorization.

21754609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15120, while the sum is 34.

The square root of 21754609 is about 4664.1836370366. The cubic root of 21754609 is about 279.1582244223.

The spelling of 21754609 in words is "twenty-one million, seven hundred fifty-four thousand, six hundred nine".