21478741 has 2 divisors, whose sum is σ = 21478742. Its totient is φ = 21478740.

The previous prime is 21478739. The next prime is 21478781. The reversal of 21478741 is 14787412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17255716 + 4223025 = 4154^2 + 2055^2 .

It is a cyclic number.

It is not a de Polignac number, because 21478741 - 2¹ = 21478739 is a prime.

It is a super-2 number, since 2×21478741² = 922672629890162, which contains 22 as substring.

Together with 21478739, it forms a pair of twin primes.

It is an alternating number because its digits alternate between even and odd.

It is a junction number, because it is equal to n+sod(n) for n = 21478697 and 21478706.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21478781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10739370 + 10739371.

It is an arithmetic number, because the mean of its divisors is an integer number (10739371).

Almost surely, 2^21478741 is an apocalyptic number.

It is an amenable number.

21478741 is a deficient number, since it is larger than the sum of its proper divisors (1).

21478741 is an equidigital number, since it uses as much as digits as its factorization.

21478741 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12544, while the sum is 34.

The square root of 21478741 is about 4634.5162638618. The cubic root of 21478741 is about 277.9732087771.

The spelling of 21478741 in words is "twenty-one million, four hundred seventy-eight thousand, seven hundred forty-one".