991553423901101 has 2 divisors, whose sum is σ = 991553423901102. Its totient is φ = 991553423901100.

The previous prime is 991553423901097. The next prime is 991553423901137. The reversal of 991553423901101 is 101109324355199.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 945938609893225 + 45614814007876 = 30756115^2 + 6753874^2 .

It is an emirp because it is prime and its reverse (101109324355199) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 991553423901101 - 2² = 991553423901097 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (991553423901151) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495776711950550 + 495776711950551.

It is an arithmetic number, because the mean of its divisors is an integer number (495776711950551).

Almost surely, 2^{991553423901101} is an apocalyptic number.

It is an amenable number.

991553423901101 is a deficient number, since it is larger than the sum of its proper divisors (1).

991553423901101 is an equidigital number, since it uses as much as digits as its factorization.

991553423901101 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1312200, while the sum is 53.

The spelling of 991553423901101 in words is "nine hundred ninety-one trillion, five hundred fifty-three billion, four hundred twenty-three million, nine hundred one thousand, one hundred one".