20217890 has 96 divisors (see below), whose sum is σ = 48066048. Its totient is φ = 6098400.

The previous prime is 20217839. The next prime is 20217931. The reversal of 20217890 is 9871202.

It is a happy number.

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 47 ways as a sum of consecutive naturals, for example, 652175 + ... + 652205.

It is an arithmetic number, because the mean of its divisors is an integer number (500688).

Almost surely, 2^20217890 is an apocalyptic number.

20217890 is an abundant number, since it is smaller than the sum of its proper divisors (27848158).

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

20217890 is a wasteful number, since it uses less digits than its factorization.

20217890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85 (or 56 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 29.

The square root of 20217890 is about 4496.4308067622. The cubic root of 20217890 is about 272.4239442095.

The spelling of 20217890 in words is "twenty million, two hundred seventeen thousand, eight hundred ninety".