9841994217557 has 4 divisors (see below), whose sum is σ = 9980613854496. Its totient is φ = 9703374580620.

The previous prime is 9841994217553. The next prime is 9841994217569. The reversal of 9841994217557 is 7557124991489.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 9841994217557 - 2² = 9841994217553 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (71), and also a Moran number because the ratio is a prime number: 138619636867 = 9841994217557 / (9 + 8 + 4 + 1 + 9 + 9 + 4 + 2 + 1 + 7 + 5 + 5 + 7).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9841994217551) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 69309818363 + ... + 69309818504.

It is an arithmetic number, because the mean of its divisors is an integer number (2495153463624).

Almost surely, 2^{9841994217557} is an apocalyptic number.

It is an amenable number.

9841994217557 is a deficient number, since it is larger than the sum of its proper divisors (138619636939).

9841994217557 is a wasteful number, since it uses less digits than its factorization.

9841994217557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 138619636938.

The product of its digits is 228614400, while the sum is 71.

The spelling of 9841994217557 in words is "nine trillion, eight hundred forty-one billion, nine hundred ninety-four million, two hundred seventeen thousand, five hundred fifty-seven".