999981684451 has 2 divisors, whose sum is σ = 999981684452. Its totient is φ = 999981684450.

The previous prime is 999981684409. The next prime is 999981684511. The reversal of 999981684451 is 154486189999.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-999981684451 is a prime.

It is not a weakly prime, because it can be changed into another prime (999961684451) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499990842225 + 499990842226.

It is an arithmetic number, because the mean of its divisors is an integer number (499990842226).

Almost surely, 2^999981684451 is an apocalyptic number.

999981684451 is the 447210-th centered decagonal number.

999981684451 is a deficient number, since it is larger than the sum of its proper divisors (1).

999981684451 is an equidigital number, since it uses as much as digits as its factorization.

999981684451 is an evil number, because the sum of its binary digits is even.

The product of its digits is 201553920, while the sum is 73.

The spelling of 999981684451 in words is "nine hundred ninety-nine billion, nine hundred eighty-one million, six hundred eighty-four thousand, four hundred fifty-one".