21584461 has 2 divisors, whose sum is σ = 21584462. Its totient is φ = 21584460.

The previous prime is 21584417. The next prime is 21584473. The reversal of 21584461 is 16448512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11222500 + 10361961 = 3350^2 + 3219^2 .

It is a cyclic number.

It is not a de Polignac number, because 21584461 - 2⁹ = 21583949 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21584411) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10792230 + 10792231.

It is an arithmetic number, because the mean of its divisors is an integer number (10792231).

Almost surely, 2^21584461 is an apocalyptic number.

It is an amenable number.

21584461 is a deficient number, since it is larger than the sum of its proper divisors (1).

21584461 is an equidigital number, since it uses as much as digits as its factorization.

21584461 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7680, while the sum is 31.

The square root of 21584461 is about 4645.9079844526. The cubic root of 21584461 is about 278.4285309876.

The spelling of 21584461 in words is "twenty-one million, five hundred eighty-four thousand, four hundred sixty-one".