20861261653 has 2 divisors, whose sum is σ = 20861261654. Its totient is φ = 20861261652.

The previous prime is 20861261599. The next prime is 20861261689. The reversal of 20861261653 is 35616216802.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11551520484 + 9309741169 = 107478^2 + 96487^2 .

It is a cyclic number.

It is not a de Polignac number, because 20861261653 - 2²⁵ = 20827707221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20861261353) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10430630826 + 10430630827.

It is an arithmetic number, because the mean of its divisors is an integer number (10430630827).

Almost surely, 2^20861261653 is an apocalyptic number.

It is an amenable number.

20861261653 is a deficient number, since it is larger than the sum of its proper divisors (1).

20861261653 is an equidigital number, since it uses as much as digits as its factorization.

20861261653 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 103680, while the sum is 40.

The spelling of 20861261653 in words is "twenty billion, eight hundred sixty-one million, two hundred sixty-one thousand, six hundred fifty-three".