1998623105 has 16 divisors (see below), whose sum is σ = 2601368784. Its totient is φ = 1468139520.

The previous prime is 1998623059. The next prime is 1998623153. The reversal of 1998623105 is 5013268991.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 523448641 + 1475174464 = 22879^2 + 38408^2 .

It is not a de Polignac number, because 1998623105 - 2¹² = 1998619009 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 283262 + ... + 290231.

It is an arithmetic number, because the mean of its divisors is an integer number (162585549).

Almost surely, 2^1998623105 is an apocalyptic number.

It is an amenable number.

1998623105 is a deficient number, since it is larger than the sum of its proper divisors (602745679).

1998623105 is a wasteful number, since it uses less digits than its factorization.

1998623105 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 573556.

The product of its (nonzero) digits is 116640, while the sum is 44.

The square root of 1998623105 is about 44705.9627454773. The cubic root of 1998623105 is about 1259.6318536869.

The spelling of 1998623105 in words is "one billion, nine hundred ninety-eight million, six hundred twenty-three thousand, one hundred five".