21711020087 has 2 divisors, whose sum is σ = 21711020088. Its totient is φ = 21711020086.

The previous prime is 21711020083. The next prime is 21711020101. The reversal of 21711020087 is 78002011712.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21711020087 - 2² = 21711020083 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21711020083) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10855510043 + 10855510044.

It is an arithmetic number, because the mean of its divisors is an integer number (10855510044).

Almost surely, 2^21711020087 is an apocalyptic number.

21711020087 is a deficient number, since it is larger than the sum of its proper divisors (1).

21711020087 is an equidigital number, since it uses as much as digits as its factorization.

21711020087 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1568, while the sum is 29.

Adding to 21711020087 its reverse (78002011712), we get a palindrome (99713031799).

The spelling of 21711020087 in words is "twenty-one billion, seven hundred eleven million, twenty thousand, eighty-seven".