21443421037 has 2 divisors, whose sum is σ = 21443421038. Its totient is φ = 21443421036.

The previous prime is 21443421031. The next prime is 21443421101. The reversal of 21443421037 is 73012434412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12519595881 + 8923825156 = 111891^2 + 94466^2 .

It is a cyclic number.

It is not a de Polignac number, because 21443421037 - 2¹⁹ = 21442896749 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21443421031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10721710518 + 10721710519.

It is an arithmetic number, because the mean of its divisors is an integer number (10721710519).

Almost surely, 2^21443421037 is an apocalyptic number.

It is an amenable number.

21443421037 is a deficient number, since it is larger than the sum of its proper divisors (1).

21443421037 is an equidigital number, since it uses as much as digits as its factorization.

21443421037 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16128, while the sum is 31.

Adding to 21443421037 its reverse (73012434412), we get a palindrome (94455855449).

The spelling of 21443421037 in words is "twenty-one billion, four hundred forty-three million, four hundred twenty-one thousand, thirty-seven".