21319477 has 2 divisors, whose sum is σ = 21319478. Its totient is φ = 21319476.

The previous prime is 21319471. The next prime is 21319481. The reversal of 21319477 is 77491312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18740241 + 2579236 = 4329^2 + 1606^2 .

It is a cyclic number.

It is not a de Polignac number, because 21319477 - 2¹⁵ = 21286709 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21319471) 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, 10659738 + 10659739.

It is an arithmetic number, because the mean of its divisors is an integer number (10659739).

Almost surely, 2^21319477 is an apocalyptic number.

It is an amenable number.

21319477 is a deficient number, since it is larger than the sum of its proper divisors (1).

21319477 is an equidigital number, since it uses as much as digits as its factorization.

21319477 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10584, while the sum is 34.

The square root of 21319477 is about 4617.3019177871. The cubic root of 21319477 is about 277.2844502043.

The spelling of 21319477 in words is "twenty-one million, three hundred nineteen thousand, four hundred seventy-seven".