999998924451781 has 2 divisors, whose sum is σ = 999998924451782. Its totient is φ = 999998924451780.

The previous prime is 999998924451619. The next prime is 999998924451799. The reversal of 999998924451781 is 187154429899999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 942015192214756 + 57983732237025 = 30692266^2 + 7614705^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-999998924451781 is a prime.

It is a super-2 number, since 2×999998924451781² (a number of 31 digits) contains 22 as substring.

It is a pancake number, because a pancake can be divided into 999998924451781 parts by 44721335 straight cuts.

It is a self number, because there is not a number n which added to its sum of digits gives 999998924451781.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (999998924451481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499999462225890 + 499999462225891.

It is an arithmetic number, because the mean of its divisors is an integer number (499999462225891).

Almost surely, 2^{999998924451781} is an apocalyptic number.

It is an amenable number.

999998924451781 is a deficient number, since it is larger than the sum of its proper divisors (1).

999998924451781 is an equidigital number, since it uses as much as digits as its factorization.

999998924451781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 38093690880, while the sum is 94.

The spelling of 999998924451781 in words is "nine hundred ninety-nine trillion, nine hundred ninety-eight billion, nine hundred twenty-four million, four hundred fifty-one thousand, seven hundred eighty-one".