20017990 has 8 divisors (see below), whose sum is σ = 36032400. Its totient is φ = 8007192.

The previous prime is 20017973. The next prime is 20017997. The reversal of 20017990 is 9971002.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20017997) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1000890 + ... + 1000909.

It is an arithmetic number, because the mean of its divisors is an integer number (4504050).

Almost surely, 2^20017990 is an apocalyptic number.

20017990 is a deficient number, since it is larger than the sum of its proper divisors (16014410).

20017990 is a wasteful number, since it uses less digits than its factorization.

20017990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2001806.

The product of its (nonzero) digits is 1134, while the sum is 28.

The square root of 20017990 is about 4474.1468460479. The cubic root of 20017990 is about 271.5231245573.

Adding to 20017990 its reverse (9971002), we get a palindrome (29988992).

The spelling of 20017990 in words is "twenty million, seventeen thousand, nine hundred ninety".