20561632 has 96 divisors (see below), whose sum is σ = 52157952. Its totient is φ = 7755264.

The previous prime is 20561621. The next prime is 20561633. The reversal of 20561632 is 23616502.

It is a junction number, because it is equal to n+sod(n) for n = 20561597 and 20561606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20561633) 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, 66823 + ... + 67129.

It is an arithmetic number, because the mean of its divisors is an integer number (543312).

Almost surely, 2^20561632 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 20561632, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26078976).

20561632 is an abundant number, since it is smaller than the sum of its proper divisors (31596320).

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

20561632 is a wasteful number, since it uses less digits than its factorization.

20561632 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 360 (or 352 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 25.

The square root of 20561632 is about 4534.4935770161. The cubic root of 20561632 is about 273.9591819424.

The spelling of 20561632 in words is "twenty million, five hundred sixty-one thousand, six hundred thirty-two".