9855971381 has 2 divisors, whose sum is σ = 9855971382. Its totient is φ = 9855971380.

The previous prime is 9855971353. The next prime is 9855971387. The reversal of 9855971381 is 1831795589.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7127580625 + 2728390756 = 84425^2 + 52234^2 .

It is a cyclic number.

It is not a de Polignac number, because 9855971381 - 2¹⁰ = 9855970357 is a prime.

It is a super-2 number, since 2×9855971381² (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 (9855971387) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4927985690 + 4927985691.

It is an arithmetic number, because the mean of its divisors is an integer number (4927985691).

Almost surely, 2^9855971381 is an apocalyptic number.

It is an amenable number.

9855971381 is a deficient number, since it is larger than the sum of its proper divisors (1).

9855971381 is an equidigital number, since it uses as much as digits as its factorization.

9855971381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2721600, while the sum is 56.

The square root of 9855971381 is about 99277.2450312759. The cubic root of 9855971381 is about 2144.0412891549.

The spelling of 9855971381 in words is "nine billion, eight hundred fifty-five million, nine hundred seventy-one thousand, three hundred eighty-one".