20661632 has 32 divisors (see below), whose sum is σ = 41473200. Its totient is φ = 10252800.

The previous prime is 20661631. The next prime is 20661643. The reversal of 20661632 is 23616602.

It is a tau number, because it is divible by the number of its divisors (32).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20661631) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18794 + ... + 19862.

Almost surely, 2^20661632 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 20661632, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20736600).

20661632 is an abundant number, since it is smaller than the sum of its proper divisors (20811568).

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

20661632 is a wasteful number, since it uses less digits than its factorization.

20661632 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1234 (or 1222 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 26.

The square root of 20661632 is about 4545.5067924270. The cubic root of 20661632 is about 274.4025907328.

The spelling of 20661632 in words is "twenty million, six hundred sixty-one thousand, six hundred thirty-two".