21312540287 has 2 divisors, whose sum is σ = 21312540288. Its totient is φ = 21312540286.

The previous prime is 21312540251. The next prime is 21312540299. The reversal of 21312540287 is 78204521312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21312540287 - 2¹² = 21312536191 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21312540187) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10656270143 + 10656270144.

It is an arithmetic number, because the mean of its divisors is an integer number (10656270144).

Almost surely, 2^21312540287 is an apocalyptic number.

21312540287 is a deficient number, since it is larger than the sum of its proper divisors (1).

21312540287 is an equidigital number, since it uses as much as digits as its factorization.

21312540287 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 26880, while the sum is 35.

The spelling of 21312540287 in words is "twenty-one billion, three hundred twelve million, five hundred forty thousand, two hundred eighty-seven".