21478304489 has 2 divisors, whose sum is σ = 21478304490. Its totient is φ = 21478304488.

The previous prime is 21478304473. The next prime is 21478304557. The reversal of 21478304489 is 98440387412.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12316560400 + 9161744089 = 110980^2 + 95717^2 .

It is a cyclic number.

It is not a de Polignac number, because 21478304489 - 2⁴ = 21478304473 is a prime.

It is a super-2 number, since 2×21478304489² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21478304789) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10739152244 + 10739152245.

It is an arithmetic number, because the mean of its divisors is an integer number (10739152245).

Almost surely, 2^21478304489 is an apocalyptic number.

It is an amenable number.

21478304489 is a deficient number, since it is larger than the sum of its proper divisors (1).

21478304489 is an equidigital number, since it uses as much as digits as its factorization.

21478304489 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1548288, while the sum is 50.

The spelling of 21478304489 in words is "twenty-one billion, four hundred seventy-eight million, three hundred four thousand, four hundred eighty-nine".