21478049 has 2 divisors, whose sum is σ = 21478050. Its totient is φ = 21478048.

The previous prime is 21478007. The next prime is 21478057. The reversal of 21478049 is 94087412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12285025 + 9193024 = 3505^2 + 3032^2 .

It is a cyclic number.

It is not a de Polignac number, because 21478049 - 2⁸ = 21477793 is a prime.

It is a super-2 number, since 2×21478049² = 922613177692802, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21478069) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10739024 + 10739025.

It is an arithmetic number, because the mean of its divisors is an integer number (10739025).

Almost surely, 2^21478049 is an apocalyptic number.

It is an amenable number.

21478049 is a deficient number, since it is larger than the sum of its proper divisors (1).

21478049 is an equidigital number, since it uses as much as digits as its factorization.

21478049 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16128, while the sum is 35.

The square root of 21478049 is about 4634.4416060622. The cubic root of 21478049 is about 277.9702235071.

The spelling of 21478049 in words is "twenty-one million, four hundred seventy-eight thousand, forty-nine".