20731648 has 72 divisors (see below), whose sum is σ = 49448448. Its totient is φ = 8481792.

The previous prime is 20731637. The next prime is 20731651. The reversal of 20731648 is 84613702.

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, 40965 + ... + 41467.

It is an arithmetic number, because the mean of its divisors is an integer number (686784).

Almost surely, 2^20731648 is an apocalyptic number.

20731648 is a gapful number since it is divisible by the number (28) 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 20731648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24724224).

20731648 is an abundant number, since it is smaller than the sum of its proper divisors (28716800).

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

20731648 is an equidigital number, since it uses as much as digits as its factorization.

20731648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 549 (or 535 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 31.

The square root of 20731648 is about 4553.2019502763. The cubic root of 20731648 is about 274.7121969746.

It can be divided in two parts, 2073 and 1648, that added together give a square (3721 = 61²).

The spelling of 20731648 in words is "twenty million, seven hundred thirty-one thousand, six hundred forty-eight".