20387832781 has 2 divisors, whose sum is σ = 20387832782. Its totient is φ = 20387832780.

The previous prime is 20387832763. The next prime is 20387832847. The reversal of 20387832781 is 18723878302.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19947042756 + 440790025 = 141234^2 + 20995^2 .

It is a cyclic number.

It is not a de Polignac number, because 20387832781 - 2⁵ = 20387832749 is a prime.

It is a super-2 number, since 2×20387832781² (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 (20387832721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10193916390 + 10193916391.

It is an arithmetic number, because the mean of its divisors is an integer number (10193916391).

Almost surely, 2^20387832781 is an apocalyptic number.

It is an amenable number.

20387832781 is a deficient number, since it is larger than the sum of its proper divisors (1).

20387832781 is an equidigital number, since it uses as much as digits as its factorization.

20387832781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 903168, while the sum is 49.

The spelling of 20387832781 in words is "twenty billion, three hundred eighty-seven million, eight hundred thirty-two thousand, seven hundred eighty-one".