21478333 has 2 divisors, whose sum is σ = 21478334. Its totient is φ = 21478332.

The previous prime is 21478313. The next prime is 21478337. The reversal of 21478333 is 33387412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15539364 + 5938969 = 3942^2 + 2437^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21478333 is a prime.

It is a super-2 number, since 2×21478333² = 922637576917778, which contains 22 as substring.

It is a plaindrome in base 16.

It is a junction number, because it is equal to n+sod(n) for n = 21478295 and 21478304.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21478337) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10739166 + 10739167.

It is an arithmetic number, because the mean of its divisors is an integer number (10739167).

Almost surely, 2^21478333 is an apocalyptic number.

It is an amenable number.

21478333 is a deficient number, since it is larger than the sum of its proper divisors (1).

21478333 is an equidigital number, since it uses as much as digits as its factorization.

21478333 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12096, while the sum is 31.

The square root of 21478333 is about 4634.4722461139. The cubic root of 21478333 is about 277.9714486835.

The spelling of 21478333 in words is "twenty-one million, four hundred seventy-eight thousand, three hundred thirty-three".