21872350117 has 2 divisors, whose sum is σ = 21872350118. Its totient is φ = 21872350116.

The previous prime is 21872350063. The next prime is 21872350121. The reversal of 21872350117 is 71105327812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12294596161 + 9577753956 = 110881^2 + 97866^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21872350117 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21872350187) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10936175058 + 10936175059.

It is an arithmetic number, because the mean of its divisors is an integer number (10936175059).

Almost surely, 2^21872350117 is an apocalyptic number.

It is an amenable number.

21872350117 is a deficient number, since it is larger than the sum of its proper divisors (1).

21872350117 is an equidigital number, since it uses as much as digits as its factorization.

21872350117 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23520, while the sum is 37.

Adding to 21872350117 its reverse (71105327812), we get a palindrome (92977677929).

The spelling of 21872350117 in words is "twenty-one billion, eight hundred seventy-two million, three hundred fifty thousand, one hundred seventeen".