20217984 has 64 divisors (see below), whose sum is σ = 55194240. Its totient is φ = 6552576.

The previous prime is 20217949. The next prime is 20218013. The reversal of 20217984 is 48971202.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (64).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13497 + ... + 14919.

It is an arithmetic number, because the mean of its divisors is an integer number (862410).

Almost surely, 2^20217984 is an apocalyptic number.

20217984 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20217984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27597120).

20217984 is an abundant number, since it is smaller than the sum of its proper divisors (34976256).

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

20217984 is a wasteful number, since it uses less digits than its factorization.

20217984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1477 (or 1465 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 33.

The square root of 20217984 is about 4496.4412594851. The cubic root of 20217984 is about 272.4243664067.

The spelling of 20217984 in words is "twenty million, two hundred seventeen thousand, nine hundred eighty-four".