21203031277 has 2 divisors, whose sum is σ = 21203031278. Its totient is φ = 21203031276.

The previous prime is 21203031257. The next prime is 21203031299. The reversal of 21203031277 is 77213030212.

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., 10639097316 + 10563933961 = 103146^2 + 102781^2 .

It is a cyclic number.

It is not a de Polignac number, because 21203031277 - 2⁷ = 21203031149 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21203031257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10601515638 + 10601515639.

It is an arithmetic number, because the mean of its divisors is an integer number (10601515639).

Almost surely, 2^21203031277 is an apocalyptic number.

It is an amenable number.

21203031277 is a deficient number, since it is larger than the sum of its proper divisors (1).

21203031277 is an equidigital number, since it uses as much as digits as its factorization.

21203031277 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3528, while the sum is 28.

Adding to 21203031277 its reverse (77213030212), we get a palindrome (98416061489).

The spelling of 21203031277 in words is "twenty-one billion, two hundred three million, thirty-one thousand, two hundred seventy-seven".