20616165491 has 2 divisors, whose sum is σ = 20616165492. Its totient is φ = 20616165490.

The previous prime is 20616165463. The next prime is 20616165503. The reversal of 20616165491 is 19456161602.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20616165491 - 2³⁴ = 3436296307 is a prime.

It is not a weakly prime, because it can be changed into another prime (20616162491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10308082745 + 10308082746.

It is an arithmetic number, because the mean of its divisors is an integer number (10308082746).

Almost surely, 2^20616165491 is an apocalyptic number.

20616165491 is a deficient number, since it is larger than the sum of its proper divisors (1).

20616165491 is an equidigital number, since it uses as much as digits as its factorization.

20616165491 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 77760, while the sum is 41.

The spelling of 20616165491 in words is "twenty billion, six hundred sixteen million, one hundred sixty-five thousand, four hundred ninety-one".