21885018973 has 2 divisors, whose sum is σ = 21885018974. Its totient is φ = 21885018972.

The previous prime is 21885018971. The next prime is 21885019001. The reversal of 21885018973 is 37981058812.

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., 21656948569 + 228070404 = 147163^2 + 15102^2 .

It is a cyclic number.

It is not a de Polignac number, because 21885018973 - 2¹ = 21885018971 is a prime.

Together with 21885018971, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 21885018973.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21885018971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10942509486 + 10942509487.

It is an arithmetic number, because the mean of its divisors is an integer number (10942509487).

Almost surely, 2^21885018973 is an apocalyptic number.

It is an amenable number.

21885018973 is a deficient number, since it is larger than the sum of its proper divisors (1).

21885018973 is an equidigital number, since it uses as much as digits as its factorization.

21885018973 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 967680, while the sum is 52.

The spelling of 21885018973 in words is "twenty-one billion, eight hundred eighty-five million, eighteen thousand, nine hundred seventy-three".