20665210537 has 2 divisors, whose sum is σ = 20665210538. Its totient is φ = 20665210536.

The previous prime is 20665210493. The next prime is 20665210547. The reversal of 20665210537 is 73501256602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19730135296 + 935075241 = 140464^2 + 30579^2 .

It is a cyclic number.

It is not a de Polignac number, because 20665210537 - 2¹⁵ = 20665177769 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20665210496 and 20665210505.

It is not a weakly prime, because it can be changed into another prime (20665210547) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10332605268 + 10332605269.

It is an arithmetic number, because the mean of its divisors is an integer number (10332605269).

Almost surely, 2^20665210537 is an apocalyptic number.

It is an amenable number.

20665210537 is a deficient number, since it is larger than the sum of its proper divisors (1).

20665210537 is an equidigital number, since it uses as much as digits as its factorization.

20665210537 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 75600, while the sum is 37.

The spelling of 20665210537 in words is "twenty billion, six hundred sixty-five million, two hundred ten thousand, five hundred thirty-seven".