20990016 has 70 divisors (see below), whose sum is σ = 62236350. Its totient is φ = 6994944.

The previous prime is 20989987. The next prime is 20990023. The reversal of 20990016 is 61009902.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 15681600 + 5308416 = 3960^2 + 2304^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 3160 + ... + 7208.

Almost surely, 2^20990016 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20990016, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31118175).

20990016 is an abundant number, since it is smaller than the sum of its proper divisors (41246334).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20990016 is an equidigital number, since it uses as much as digits as its factorization.

20990016 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4073 (or 4054 counting only the distinct ones).

The product of its (nonzero) digits is 972, while the sum is 27.

The square root of 20990016 is about 4581.4862217407. The cubic root of 20990016 is about 275.8486883280.

Adding to 20990016 its reverse (61009902), we get a palindrome (81999918).

The spelling of 20990016 in words is "twenty million, nine hundred ninety thousand, sixteen".