20531766641 has 2 divisors, whose sum is σ = 20531766642. Its totient is φ = 20531766640.

The previous prime is 20531766601. The next prime is 20531766701. The reversal of 20531766641 is 14666713502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13341405025 + 7190361616 = 115505^2 + 84796^2 .

It is a cyclic number.

It is not a de Polignac number, because 20531766641 - 2¹⁴ = 20531750257 is a prime.

It is not a weakly prime, because it can be changed into another prime (20531766601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10265883320 + 10265883321.

It is an arithmetic number, because the mean of its divisors is an integer number (10265883321).

Almost surely, 2^20531766641 is an apocalyptic number.

It is an amenable number.

20531766641 is a deficient number, since it is larger than the sum of its proper divisors (1).

20531766641 is an equidigital number, since it uses as much as digits as its factorization.

20531766641 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 181440, while the sum is 41.

The spelling of 20531766641 in words is "twenty billion, five hundred thirty-one million, seven hundred sixty-six thousand, six hundred forty-one".