20916990 has 24 divisors (see below), whose sum is σ = 54384408. Its totient is φ = 5577840.

The previous prime is 20916979. The next prime is 20916997. The reversal of 20916990 is 9961902.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20916997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 116116 + ... + 116295.

It is an arithmetic number, because the mean of its divisors is an integer number (2266017).

Almost surely, 2^20916990 is an apocalyptic number.

20916990 is an abundant number, since it is smaller than the sum of its proper divisors (33467418).

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

20916990 is a wasteful number, since it uses less digits than its factorization.

20916990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 232424 (or 232421 counting only the distinct ones).

The product of its (nonzero) digits is 8748, while the sum is 36.

The square root of 20916990 is about 4573.5095932992. The cubic root of 20916990 is about 275.5284164966.

The spelling of 20916990 in words is "twenty million, nine hundred sixteen thousand, nine hundred ninety".