20643312 has 40 divisors (see below), whose sum is σ = 53517904. Its totient is φ = 6856704.

The previous prime is 20643269. The next prime is 20643313. The reversal of 20643312 is 21334602.

It is a happy number.

It is a super-2 number, since 2×20643312² = 852292660658688, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20643313) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17328 + ... + 18480.

Almost surely, 2^20643312 is an apocalyptic number.

It is an amenable number.

20643312 is an abundant number, since it is smaller than the sum of its proper divisors (32874592).

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

20643312 is a wasteful number, since it uses less digits than its factorization.

20643312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1537 (or 1531 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 21.

The square root of 20643312 is about 4543.4911686940. The cubic root of 20643312 is about 274.3214654540.

Adding to 20643312 its reverse (21334602), we get a palindrome (41977914).

The spelling of 20643312 in words is "twenty million, six hundred forty-three thousand, three hundred twelve".