20861544 has 64 divisors (see below), whose sum is σ = 59904000. Its totient is φ = 5987520.

The previous prime is 20861539. The next prime is 20861549. The reversal of 20861544 is 44516802.

It is an interprime number because it is at equal distance from previous prime (20861539) and next prime (20861549).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20861549) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2937 + ... + 7095.

It is an arithmetic number, because the mean of its divisors is an integer number (936000).

Almost surely, 2^20861544 is an apocalyptic number.

20861544 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 20861544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29952000).

20861544 is an abundant number, since it is smaller than the sum of its proper divisors (39042456).

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

20861544 is a wasteful number, since it uses less digits than its factorization.

20861544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4198 (or 4194 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 30.

The square root of 20861544 is about 4567.4439241221. The cubic root of 20861544 is about 275.2847474820.

The spelling of 20861544 in words is "twenty million, eight hundred sixty-one thousand, five hundred forty-four".