21448477 has 2 divisors, whose sum is σ = 21448478. Its totient is φ = 21448476.

The previous prime is 21448463. The next prime is 21448481. The reversal of 21448477 is 77484412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19838116 + 1610361 = 4454^2 + 1269^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21448477 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21448457) 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, 10724238 + 10724239.

It is an arithmetic number, because the mean of its divisors is an integer number (10724239).

Almost surely, 2^21448477 is an apocalyptic number.

It is an amenable number.

21448477 is a deficient number, since it is larger than the sum of its proper divisors (1).

21448477 is an equidigital number, since it uses as much as digits as its factorization.

21448477 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 50176, while the sum is 37.

The square root of 21448477 is about 4631.2500472335. The cubic root of 21448477 is about 277.8425907014.

The spelling of 21448477 in words is "twenty-one million, four hundred forty-eight thousand, four hundred seventy-seven".