21126009977 has 2 divisors, whose sum is σ = 21126009978. Its totient is φ = 21126009976.

The previous prime is 21126009967. The next prime is 21126010057. The reversal of 21126009977 is 77990062112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19109191696 + 2016818281 = 138236^2 + 44909^2 .

It is a cyclic number.

It is not a de Polignac number, because 21126009977 - 2²⁴ = 21109232761 is a prime.

It is not a weakly prime, because it can be changed into another prime (21126009907) 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, 10563004988 + 10563004989.

It is an arithmetic number, because the mean of its divisors is an integer number (10563004989).

Almost surely, 2^21126009977 is an apocalyptic number.

It is an amenable number.

21126009977 is a deficient number, since it is larger than the sum of its proper divisors (1).

21126009977 is an equidigital number, since it uses as much as digits as its factorization.

21126009977 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 95256, while the sum is 44.

The spelling of 21126009977 in words is "twenty-one billion, one hundred twenty-six million, nine thousand, nine hundred seventy-seven".