213121019977 has 2 divisors, whose sum is σ = 213121019978. Its totient is φ = 213121019976.

The previous prime is 213121019939. The next prime is 213121020001. The reversal of 213121019977 is 779910121312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 194992013241 + 18129006736 = 441579^2 + 134644^2 .

It is a cyclic number.

It is not a de Polignac number, because 213121019977 - 2⁷ = 213121019849 is a prime.

It is not a weakly prime, because it can be changed into another prime (213121013977) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106560509988 + 106560509989.

It is an arithmetic number, because the mean of its divisors is an integer number (106560509989).

Almost surely, 2^213121019977 is an apocalyptic number.

It is an amenable number.

213121019977 is a deficient number, since it is larger than the sum of its proper divisors (1).

213121019977 is an equidigital number, since it uses as much as digits as its factorization.

213121019977 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 47628, while the sum is 43.

The spelling of 213121019977 in words is "two hundred thirteen billion, one hundred twenty-one million, nineteen thousand, nine hundred seventy-seven".