21000010099973 has 2 divisors, whose sum is σ = 21000010099974. Its totient is φ = 21000010099972.

The previous prime is 21000010099963. The next prime is 21000010100021. The reversal of 21000010099973 is 37999001000012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18577884382849 + 2422125717124 = 4310207^2 + 1556318^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21000010099973 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21000010099973.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21000010099963) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500005049986 + 10500005049987.

It is an arithmetic number, because the mean of its divisors is an integer number (10500005049987).

Almost surely, 2^{21000010099973} is an apocalyptic number.

It is an amenable number.

21000010099973 is a deficient number, since it is larger than the sum of its proper divisors (1).

21000010099973 is an equidigital number, since it uses as much as digits as its factorization.

21000010099973 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 30618, while the sum is 41.

Adding to 21000010099973 its reverse (37999001000012), we get a palindrome (58999011099985).

The spelling of 21000010099973 in words is "twenty-one trillion, ten million, ninety-nine thousand, nine hundred seventy-three".