21515410289887 has 2 divisors, whose sum is σ = 21515410289888. Its totient is φ = 21515410289886.

The previous prime is 21515410289803. The next prime is 21515410289899. The reversal of 21515410289887 is 78898201451512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21515410289887 - 2¹⁵ = 21515410257119 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21515410287887) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10757705144943 + 10757705144944.

It is an arithmetic number, because the mean of its divisors is an integer number (10757705144944).

Almost surely, 2^{21515410289887} is an apocalyptic number.

21515410289887 is a deficient number, since it is larger than the sum of its proper divisors (1).

21515410289887 is an equidigital number, since it uses as much as digits as its factorization.

21515410289887 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12902400, while the sum is 61.

The spelling of 21515410289887 in words is "twenty-one trillion, five hundred fifteen billion, four hundred ten million, two hundred eighty-nine thousand, eight hundred eighty-seven".