21722221057 has 2 divisors, whose sum is σ = 21722221058. Its totient is φ = 21722221056.

The previous prime is 21722221043. The next prime is 21722221069. The reversal of 21722221057 is 75012222712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13906069776 + 7816151281 = 117924^2 + 88409^2 .

It is a cyclic number.

It is not a de Polignac number, because 21722221057 - 2¹¹ = 21722219009 is a prime.

It is not a weakly prime, because it can be changed into another prime (21722222057) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10861110528 + 10861110529.

It is an arithmetic number, because the mean of its divisors is an integer number (10861110529).

Almost surely, 2^21722221057 is an apocalyptic number.

It is an amenable number.

21722221057 is a deficient number, since it is larger than the sum of its proper divisors (1).

21722221057 is an equidigital number, since it uses as much as digits as its factorization.

21722221057 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7840, while the sum is 31.

Adding to 21722221057 its reverse (75012222712), we get a palindrome (96734443769).

The spelling of 21722221057 in words is "twenty-one billion, seven hundred twenty-two million, two hundred twenty-one thousand, fifty-seven".