999661028731 has 2 divisors, whose sum is σ = 999661028732. Its totient is φ = 999661028730.

The previous prime is 999661028719. The next prime is 999661028789. The reversal of 999661028731 is 137820166999.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 999661028731 - 2¹³ = 999661020539 is a prime.

It is a super-2 number, since 2×999661028731² (a number of 25 digits) contains 22 as substring.

It is the 999831-st Hogben number.

It is a self number, because there is not a number n which added to its sum of digits gives 999661028731.

It is not a weakly prime, because it can be changed into another prime (999661025731) by changing a digit.

It is a nontrivial repunit in base 999830.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499830514365 + 499830514366.

It is an arithmetic number, because the mean of its divisors is an integer number (499830514366).

Almost surely, 2^999661028731 is an apocalyptic number.

999661028731 is a deficient number, since it is larger than the sum of its proper divisors (1).

999661028731 is an equidigital number, since it uses as much as digits as its factorization.

999661028731 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8817984, while the sum is 61.

The spelling of 999661028731 in words is "nine hundred ninety-nine billion, six hundred sixty-one million, twenty-eight thousand, seven hundred thirty-one".