20284640 has 48 divisors (see below), whose sum is σ = 48453552. Its totient is φ = 8024064.

The previous prime is 20284639. The next prime is 20284651. The reversal of 20284640 is 4648202.

It is a super-2 number, since 2×20284640² = 822933239859200, which contains 22 as substring.

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, 14867 + ... + 16173.

It is an arithmetic number, because the mean of its divisors is an integer number (1009449).

Almost surely, 2^20284640 is an apocalyptic number.

20284640 is a gapful number since it is divisible by the number (20) 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 20284640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24226776).

20284640 is an abundant number, since it is smaller than the sum of its proper divisors (28168912).

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

20284640 is a wasteful number, since it uses less digits than its factorization.

20284640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1419 (or 1411 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 26.

The square root of 20284640 is about 4503.8472443013. The cubic root of 20284640 is about 272.7234202823.

The spelling of 20284640 in words is "twenty million, two hundred eighty-four thousand, six hundred forty".