20398664 has 48 divisors (see below), whose sum is σ = 45302460. Its totient is φ = 8553600.

The previous prime is 20398663. The next prime is 20398699. The reversal of 20398664 is 46689302.

It can be written as a sum of positive squares in 2 ways, for example, as 20340100 + 58564 = 4510^2 + 242^2 .

It is a super-2 number, since 2×20398664² = 832210985969792, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20398663) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 11774 + ... + 13394.

Almost surely, 2^20398664 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 20398664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22651230).

20398664 is an abundant number, since it is smaller than the sum of its proper divisors (24903796).

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

20398664 is a wasteful number, since it uses less digits than its factorization.

20398664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1662 (or 1647 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 38.

The square root of 20398664 is about 4516.4880161471. The cubic root of 20398664 is about 273.2334766444.

The spelling of 20398664 in words is "twenty million, three hundred ninety-eight thousand, six hundred sixty-four".