21873257017 has 2 divisors, whose sum is σ = 21873257018. Its totient is φ = 21873257016.

The previous prime is 21873256991. The next prime is 21873257023. The reversal of 21873257017 is 71075237812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11741022736 + 10132234281 = 108356^2 + 100659^2 .

It is a cyclic number.

It is not a de Polignac number, because 21873257017 - 2³¹ = 19725773369 is a prime.

It is not a weakly prime, because it can be changed into another prime (21873257027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10936628508 + 10936628509.

It is an arithmetic number, because the mean of its divisors is an integer number (10936628509).

Almost surely, 2^21873257017 is an apocalyptic number.

It is an amenable number.

21873257017 is a deficient number, since it is larger than the sum of its proper divisors (1).

21873257017 is an equidigital number, since it uses as much as digits as its factorization.

21873257017 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 164640, while the sum is 43.

The spelling of 21873257017 in words is "twenty-one billion, eight hundred seventy-three million, two hundred fifty-seven thousand, seventeen".