21650556511 has 2 divisors, whose sum is σ = 21650556512. Its totient is φ = 21650556510.

The previous prime is 21650556503. The next prime is 21650556539. The reversal of 21650556511 is 11565505612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21650556511 - 2³ = 21650556503 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21650556311) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10825278255 + 10825278256.

It is an arithmetic number, because the mean of its divisors is an integer number (10825278256).

Almost surely, 2^21650556511 is an apocalyptic number.

21650556511 is a deficient number, since it is larger than the sum of its proper divisors (1).

21650556511 is an equidigital number, since it uses as much as digits as its factorization.

21650556511 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 45000, while the sum is 37.

The spelling of 21650556511 in words is "twenty-one billion, six hundred fifty million, five hundred fifty-six thousand, five hundred eleven".