1666979998 has 4 divisors (see below), whose sum is σ = 2500470000. Its totient is φ = 833489998.

The previous prime is 1666979983. The next prime is 1666980013. The reversal of 1666979998 is 8999796661.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (1666979983) and next prime (1666980013).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 416744998 + ... + 416745001.

It is an arithmetic number, because the mean of its divisors is an integer number (625117500).

Almost surely, 2^1666979998 is an apocalyptic number.

1666979998 is a deficient number, since it is larger than the sum of its proper divisors (833490002).

1666979998 is an equidigital number, since it uses as much as digits as its factorization.

1666979998 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 833490001.

The product of its digits is 79361856, while the sum is 70.

The square root of 1666979998 is about 40828.6663754769. Note that the first 3 decimals coincide. The cubic root of 1666979998 is about 1185.7053959159.

It can be divided in two parts, 166 and 6979998, that added together give a square (6980164 = 2642²).

The spelling of 1666979998 in words is "one billion, six hundred sixty-six million, nine hundred seventy-nine thousand, nine hundred ninety-eight".