21579461 has 2 divisors, whose sum is σ = 21579462. Its totient is φ = 21579460.

The previous prime is 21579433. The next prime is 21579463. The reversal of 21579461 is 16497512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19272100 + 2307361 = 4390^2 + 1519^2 .

It is a cyclic number.

It is not a de Polignac number, because 21579461 - 2¹⁴ = 21563077 is a prime.

It is a Sophie Germain prime.

Together with 21579463, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21579463) 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 as a sum of consecutive naturals, namely, 10789730 + 10789731.

It is an arithmetic number, because the mean of its divisors is an integer number (10789731).

Almost surely, 2^21579461 is an apocalyptic number.

It is an amenable number.

21579461 is a deficient number, since it is larger than the sum of its proper divisors (1).

21579461 is an equidigital number, since it uses as much as digits as its factorization.

21579461 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15120, while the sum is 35.

The square root of 21579461 is about 4645.3698453406. The cubic root of 21579461 is about 278.4070301779.

The spelling of 21579461 in words is "twenty-one million, five hundred seventy-nine thousand, four hundred sixty-one".