21143021231 has 2 divisors, whose sum is σ = 21143021232. Its totient is φ = 21143021230.

The previous prime is 21143021189. The next prime is 21143021243. The reversal of 21143021231 is 13212034112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21143021231 - 2²² = 21138826927 is a prime.

It is a super-2 number, since 2×21143021231² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21143021831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10571510615 + 10571510616.

It is an arithmetic number, because the mean of its divisors is an integer number (10571510616).

Almost surely, 2^21143021231 is an apocalyptic number.

21143021231 is a deficient number, since it is larger than the sum of its proper divisors (1).

21143021231 is an equidigital number, since it uses as much as digits as its factorization.

21143021231 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 20.

Adding to 21143021231 its reverse (13212034112), we get a palindrome (34355055343).

The spelling of 21143021231 in words is "twenty-one billion, one hundred forty-three million, twenty-one thousand, two hundred thirty-one".