20657184491 has 2 divisors, whose sum is σ = 20657184492. Its totient is φ = 20657184490.

The previous prime is 20657184487. The next prime is 20657184523. The reversal of 20657184491 is 19448175602.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20657184491 - 2² = 20657184487 is a prime.

It is not a weakly prime, because it can be changed into another prime (20657184451) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10328592245 + 10328592246.

It is an arithmetic number, because the mean of its divisors is an integer number (10328592246).

Almost surely, 2^20657184491 is an apocalyptic number.

20657184491 is a deficient number, since it is larger than the sum of its proper divisors (1).

20657184491 is an equidigital number, since it uses as much as digits as its factorization.

20657184491 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 483840, while the sum is 47.

The spelling of 20657184491 in words is "twenty billion, six hundred fifty-seven million, one hundred eighty-four thousand, four hundred ninety-one".