21978107378047 has 2 divisors, whose sum is σ = 21978107378048. Its totient is φ = 21978107378046.

The previous prime is 21978107377987. The next prime is 21978107378063. The reversal of 21978107378047 is 74087370187912.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21978107378047 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21978107378047.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21978107078047) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10989053689023 + 10989053689024.

It is an arithmetic number, because the mean of its divisors is an integer number (10989053689024).

Almost surely, 2^{21978107378047} is an apocalyptic number.

21978107378047 is a deficient number, since it is larger than the sum of its proper divisors (1).

21978107378047 is an equidigital number, since it uses as much as digits as its factorization.

21978107378047 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 33191424, while the sum is 64.

The spelling of 21978107378047 in words is "twenty-one trillion, nine hundred seventy-eight billion, one hundred seven million, three hundred seventy-eight thousand, forty-seven".