20643530 has 8 divisors (see below), whose sum is σ = 37158372. Its totient is φ = 8257408.

The previous prime is 20643529. The next prime is 20643547. The reversal of 20643530 is 3534602.

It can be written as a sum of positive squares in 2 ways, for example, as 20529961 + 113569 = 4531^2 + 337^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 20643496 and 20643505.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1032167 + ... + 1032186.

Almost surely, 2^20643530 is an apocalyptic number.

20643530 is a deficient number, since it is larger than the sum of its proper divisors (16514842).

20643530 is a wasteful number, since it uses less digits than its factorization.

20643530 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2064360.

The product of its (nonzero) digits is 2160, while the sum is 23.

The square root of 20643530 is about 4543.5151589931. The cubic root of 20643530 is about 274.3224310915.

The spelling of 20643530 in words is "twenty million, six hundred forty-three thousand, five hundred thirty".