20990090 has 32 divisors (see below), whose sum is σ = 41492736. Its totient is φ = 7581760.

The previous prime is 20990071. The next prime is 20990111. The reversal of 20990090 is 9009902.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18479 + ... + 19581.

It is an arithmetic number, because the mean of its divisors is an integer number (1296648).

Almost surely, 2^20990090 is an apocalyptic number.

20990090 is a deficient number, since it is larger than the sum of its proper divisors (20502646).

20990090 is a wasteful number, since it uses less digits than its factorization.

20990090 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1294.

The product of its (nonzero) digits is 1458, while the sum is 29.

The square root of 20990090 is about 4581.4942977155. The cubic root of 20990090 is about 275.8490124945.

Adding to 20990090 its reverse (9009902), we get a palindrome (29999992).

The spelling of 20990090 in words is "twenty million, nine hundred ninety thousand, ninety".