21978478603 has 2 divisors, whose sum is σ = 21978478604. Its totient is φ = 21978478602.

The previous prime is 21978478537. The next prime is 21978478619. The reversal of 21978478603 is 30687487912.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21978478603 - 2⁹ = 21978478091 is a prime.

It is not a weakly prime, because it can be changed into another prime (21978478693) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10989239301 + 10989239302.

It is an arithmetic number, because the mean of its divisors is an integer number (10989239302).

Almost surely, 2^21978478603 is an apocalyptic number.

21978478603 is a deficient number, since it is larger than the sum of its proper divisors (1).

21978478603 is an equidigital number, since it uses as much as digits as its factorization.

21978478603 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4064256, while the sum is 55.

The spelling of 21978478603 in words is "twenty-one billion, nine hundred seventy-eight million, four hundred seventy-eight thousand, six hundred three".