21222154637 has 2 divisors, whose sum is σ = 21222154638. Its totient is φ = 21222154636.

The previous prime is 21222154627. The next prime is 21222154669. The reversal of 21222154637 is 73645122212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18091864036 + 3130290601 = 134506^2 + 55949^2 .

It is a cyclic number.

It is not a de Polignac number, because 21222154637 - 2⁴ = 21222154621 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21222154597 and 21222154606.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21222154627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10611077318 + 10611077319.

It is an arithmetic number, because the mean of its divisors is an integer number (10611077319).

Almost surely, 2^21222154637 is an apocalyptic number.

It is an amenable number.

21222154637 is a deficient number, since it is larger than the sum of its proper divisors (1).

21222154637 is an equidigital number, since it uses as much as digits as its factorization.

21222154637 is an evil number, because the sum of its binary digits is even.

The product of its digits is 40320, while the sum is 35.

Adding to 21222154637 its reverse (73645122212), we get a palindrome (94867276849).

The spelling of 21222154637 in words is "twenty-one billion, two hundred twenty-two million, one hundred fifty-four thousand, six hundred thirty-seven".