20430221437 has 2 divisors, whose sum is σ = 20430221438. Its totient is φ = 20430221436.

The previous prime is 20430221417. The next prime is 20430221473. The reversal of 20430221437 is 73412203402.

Together with next prime (20430221473) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19618484356 + 811737081 = 140066^2 + 28491^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20430221437 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20430221417) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10215110718 + 10215110719.

It is an arithmetic number, because the mean of its divisors is an integer number (10215110719).

Almost surely, 2^20430221437 is an apocalyptic number.

It is an amenable number.

20430221437 is a deficient number, since it is larger than the sum of its proper divisors (1).

20430221437 is an equidigital number, since it uses as much as digits as its factorization.

20430221437 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8064, while the sum is 28.

Adding to 20430221437 its reverse (73412203402), we get a palindrome (93842424839).

The spelling of 20430221437 in words is "twenty billion, four hundred thirty million, two hundred twenty-one thousand, four hundred thirty-seven".