20781081701 has 2 divisors, whose sum is σ = 20781081702. Its totient is φ = 20781081700.

The previous prime is 20781081689. The next prime is 20781081743. The reversal of 20781081701 is 10718018702.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18968451076 + 1812630625 = 137726^2 + 42575^2 .

It is a cyclic number.

It is not a de Polignac number, because 20781081701 - 2¹⁸ = 20780819557 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20781081901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10390540850 + 10390540851.

It is an arithmetic number, because the mean of its divisors is an integer number (10390540851).

Almost surely, 2^20781081701 is an apocalyptic number.

It is an amenable number.

20781081701 is a deficient number, since it is larger than the sum of its proper divisors (1).

20781081701 is an equidigital number, since it uses as much as digits as its factorization.

20781081701 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6272, while the sum is 35.

The spelling of 20781081701 in words is "twenty billion, seven hundred eighty-one million, eighty-one thousand, seven hundred one".