21143807989 has 2 divisors, whose sum is σ = 21143807990. Its totient is φ = 21143807988.

The previous prime is 21143807947. The next prime is 21143808011. The reversal of 21143807989 is 98970834112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13872835089 + 7270972900 = 117783^2 + 85270^2 .

It is a cyclic number.

It is not a de Polignac number, because 21143807989 - 2¹⁹ = 21143283701 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21143807189) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10571903994 + 10571903995.

It is an arithmetic number, because the mean of its divisors is an integer number (10571903995).

Almost surely, 2^21143807989 is an apocalyptic number.

It is an amenable number.

21143807989 is a deficient number, since it is larger than the sum of its proper divisors (1).

21143807989 is an equidigital number, since it uses as much as digits as its factorization.

21143807989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 870912, while the sum is 52.

The spelling of 21143807989 in words is "twenty-one billion, one hundred forty-three million, eight hundred seven thousand, nine hundred eighty-nine".