20966666477 has 2 divisors, whose sum is σ = 20966666478. Its totient is φ = 20966666476.

The previous prime is 20966666447. The next prime is 20966666519. The reversal of 20966666477 is 77466666902.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19167294916 + 1799371561 = 138446^2 + 42419^2 .

It is a cyclic number.

It is not a de Polignac number, because 20966666477 - 2⁸ = 20966666221 is a prime.

It is a super-2 number, since 2×20966666477² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20966666447) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10483333238 + 10483333239.

It is an arithmetic number, because the mean of its divisors is an integer number (10483333239).

Almost surely, 2^20966666477 is an apocalyptic number.

It is an amenable number.

20966666477 is a deficient number, since it is larger than the sum of its proper divisors (1).

20966666477 is an equidigital number, since it uses as much as digits as its factorization.

20966666477 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 27433728, while the sum is 59.

The spelling of 20966666477 in words is "twenty billion, nine hundred sixty-six million, six hundred sixty-six thousand, four hundred seventy-seven".