20531648 has 56 divisors (see below), whose sum is σ = 43781472. Its totient is φ = 9519104.

The previous prime is 20531603. The next prime is 20531657. The reversal of 20531648 is 84613502.

It is a hoax number, since the sum of its digits (29) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 20531648.

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, 122861 + ... + 123027.

It is an arithmetic number, because the mean of its divisors is an integer number (781812).

Almost surely, 2^20531648 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 20531648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21890736).

20531648 is an abundant number, since it is smaller than the sum of its proper divisors (23249824).

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

20531648 is a wasteful number, since it uses less digits than its factorization.

20531648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 309 (or 299 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 29.

The square root of 20531648 is about 4531.1861581709. The cubic root of 20531648 is about 273.8259501667.

The spelling of 20531648 in words is "twenty million, five hundred thirty-one thousand, six hundred forty-eight".