20661998 has 16 divisors (see below), whose sum is σ = 35610624. Its totient is φ = 8807640.

The previous prime is 20661989. The next prime is 20662003. The reversal of 20661998 is 89916602.

It is a super-2 number, since 2×20661998² = 853836322704008, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1190 + ... + 6537.

It is an arithmetic number, because the mean of its divisors is an integer number (2225664).

Almost surely, 2^20661998 is an apocalyptic number.

20661998 is a deficient number, since it is larger than the sum of its proper divisors (14948626).

20661998 is a wasteful number, since it uses less digits than its factorization.

20661998 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7927.

The product of its (nonzero) digits is 46656, while the sum is 41.

The square root of 20661998 is about 4545.5470517860. The cubic root of 20661998 is about 274.4042109784.

The spelling of 20661998 in words is "twenty million, six hundred sixty-one thousand, nine hundred ninety-eight".