20172984 has 128 divisors (see below), whose sum is σ = 59270400. Its totient is φ = 5667840.

The previous prime is 20172979. The next prime is 20172989. The reversal of 20172984 is 48927102.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (20172979) and next prime (20172989).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20172989) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 243007 + ... + 243089.

It is an arithmetic number, because the mean of its divisors is an integer number (463050).

Almost surely, 2^20172984 is an apocalyptic number.

20172984 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 20172984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29635200).

20172984 is an abundant number, since it is smaller than the sum of its proper divisors (39097416).

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

20172984 is a wasteful number, since it uses less digits than its factorization.

20172984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165 (or 161 counting only the distinct ones).

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

The square root of 20172984 is about 4491.4345147180. The cubic root of 20172984 is about 272.2221008900. Note that the first 3 decimals are identical.

The spelling of 20172984 in words is "twenty million, one hundred seventy-two thousand, nine hundred eighty-four".