20640030 has 32 divisors (see below), whose sum is σ = 49689504. Its totient is φ = 5486976.

The previous prime is 20640019. The next prime is 20640047. The reversal of 20640030 is 3004602.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 20639991 and 20640009.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11044 + ... + 12776.

It is an arithmetic number, because the mean of its divisors is an integer number (1552797).

Almost surely, 2^20640030 is an apocalyptic number.

20640030 is an abundant number, since it is smaller than the sum of its proper divisors (29049474).

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

20640030 is a wasteful number, since it uses less digits than its factorization.

20640030 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2140.

The product of its (nonzero) digits is 144, while the sum is 15.

The square root of 20640030 is about 4543.1299783299. The cubic root of 20640030 is about 274.3069269153.

Adding to 20640030 its reverse (3004602), we get a palindrome (23644632).

The spelling of 20640030 in words is "twenty million, six hundred forty thousand, thirty".