999784921951 has 2 divisors, whose sum is σ = 999784921952. Its totient is φ = 999784921950.

The previous prime is 999784921943. The next prime is 999784921981. The reversal of 999784921951 is 159129487999.

It is a happy number.

It is a weak prime.

It is an emirp because it is prime and its reverse (159129487999) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 999784921951 - 2³ = 999784921943 is a prime.

It is a super-3 number, since 3×999784921951³ (a number of 37 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (999784921981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499892460975 + 499892460976.

It is an arithmetic number, because the mean of its divisors is an integer number (499892460976).

Almost surely, 2^999784921951 is an apocalyptic number.

999784921951 is the 447166-th centered decagonal number.

999784921951 is a deficient number, since it is larger than the sum of its proper divisors (1).

999784921951 is an equidigital number, since it uses as much as digits as its factorization.

999784921951 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 132269760, while the sum is 73.

The spelling of 999784921951 in words is "nine hundred ninety-nine billion, seven hundred eighty-four million, nine hundred twenty-one thousand, nine hundred fifty-one".