20061640 has 32 divisors (see below), whose sum is σ = 45334080. Its totient is φ = 7989952.

The previous prime is 20061623. The next prime is 20061653. The reversal of 20061640 is 4616002.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9567 + ... + 11473.

It is an arithmetic number, because the mean of its divisors is an integer number (1416690).

Almost surely, 2^20061640 is an apocalyptic number.

20061640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20061640 is an abundant number, since it is smaller than the sum of its proper divisors (25272440).

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

20061640 is a wasteful number, since it uses less digits than its factorization.

20061640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2181 (or 2177 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 20061640 is about 4479.0222147250. The cubic root of 20061640 is about 271.7203368354.

Adding to 20061640 its reverse (4616002), we get a palindrome (24677642).

The spelling of 20061640 in words is "twenty million, sixty-one thousand, six hundred forty".