20717087381 has 2 divisors, whose sum is σ = 20717087382. Its totient is φ = 20717087380.

The previous prime is 20717087329. The next prime is 20717087401. The reversal of 20717087381 is 18378071702.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11186446756 + 9530640625 = 105766^2 + 97625^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20717087381 is a prime.

It is a super-2 number, since 2×20717087381² (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 (20717087081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10358543690 + 10358543691.

It is an arithmetic number, because the mean of its divisors is an integer number (10358543691).

Almost surely, 2^20717087381 is an apocalyptic number.

It is an amenable number.

20717087381 is a deficient number, since it is larger than the sum of its proper divisors (1).

20717087381 is an equidigital number, since it uses as much as digits as its factorization.

20717087381 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 131712, while the sum is 44.

The spelling of 20717087381 in words is "twenty billion, seven hundred seventeen million, eighty-seven thousand, three hundred eighty-one".