21241431287 has 2 divisors, whose sum is σ = 21241431288. Its totient is φ = 21241431286.

The previous prime is 21241431259. The next prime is 21241431359. The reversal of 21241431287 is 78213414212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21241431287 - 2¹² = 21241427191 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21241431187) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10620715643 + 10620715644.

It is an arithmetic number, because the mean of its divisors is an integer number (10620715644).

Almost surely, 2^21241431287 is an apocalyptic number.

21241431287 is a deficient number, since it is larger than the sum of its proper divisors (1).

21241431287 is an equidigital number, since it uses as much as digits as its factorization.

21241431287 is an evil number, because the sum of its binary digits is even.

The product of its digits is 21504, while the sum is 35.

Adding to 21241431287 its reverse (78213414212), we get a palindrome (99454845499).

The spelling of 21241431287 in words is "twenty-one billion, two hundred forty-one million, four hundred thirty-one thousand, two hundred eighty-seven".