9997781163551 has 2 divisors, whose sum is σ = 9997781163552. Its totient is φ = 9997781163550.

The previous prime is 9997781163547. The next prime is 9997781163569. The reversal of 9997781163551 is 1553611877999.

It is a weak prime.

It is an emirp because it is prime and its reverse (1553611877999) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 9997781163551 - 2² = 9997781163547 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9997781193551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4998890581775 + 4998890581776.

It is an arithmetic number, because the mean of its divisors is an integer number (4998890581776).

Almost surely, 2^{9997781163551} is an apocalyptic number.

9997781163551 is a deficient number, since it is larger than the sum of its proper divisors (1).

9997781163551 is an equidigital number, since it uses as much as digits as its factorization.

9997781163551 is an evil number, because the sum of its binary digits is even.

The product of its digits is 128595600, while the sum is 71.

The spelling of 9997781163551 in words is "nine trillion, nine hundred ninety-seven billion, seven hundred eighty-one million, one hundred sixty-three thousand, five hundred fifty-one".