21115351487 has 2 divisors, whose sum is σ = 21115351488. Its totient is φ = 21115351486.

The previous prime is 21115351469. The next prime is 21115351513. The reversal of 21115351487 is 78415351112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21115351487 - 2⁶ = 21115351423 is a prime.

It is a super-2 number, since 2×21115351487² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21115351487.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21115351087) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10557675743 + 10557675744.

It is an arithmetic number, because the mean of its divisors is an integer number (10557675744).

Almost surely, 2^21115351487 is an apocalyptic number.

21115351487 is a deficient number, since it is larger than the sum of its proper divisors (1).

21115351487 is an equidigital number, since it uses as much as digits as its factorization.

21115351487 is an evil number, because the sum of its binary digits is even.

The product of its digits is 33600, while the sum is 38.

The spelling of 21115351487 in words is "twenty-one billion, one hundred fifteen million, three hundred fifty-one thousand, four hundred eighty-seven".