999998623 has 16 divisors (see below), whose sum is σ = 1128012480. Its totient is φ = 879588864.

The previous prime is 999998621. The next prime is 999998627. The reversal of 999998623 is 326899999.

It is a cyclic number.

It is not a de Polignac number, because 999998623 - 2¹ = 999998621 is a prime.

It is a super-2 number, since 2×999998623² = 1999994492003792258, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (999998621) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 74215 + ... + 86647.

It is an arithmetic number, because the mean of its divisors is an integer number (70500780).

Almost surely, 2^999998623 is an apocalyptic number.

999998623 is a deficient number, since it is larger than the sum of its proper divisors (128013857).

999998623 is a wasteful number, since it uses less digits than its factorization.

999998623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12738.

The product of its digits is 17006112, while the sum is 64.

The square root of 999998623 is about 31622.7548293946. The cubic root of 999998623 is about 999.9995409998. Note that the first 3 decimals are identical.

The spelling of 999998623 in words is "nine hundred ninety-nine million, nine hundred ninety-eight thousand, six hundred twenty-three".