20420664240 has 40 divisors (see below), whose sum is σ = 63304059888. Its totient is φ = 5445510400.

The previous prime is 20420664239. The next prime is 20420664247. The reversal of 20420664240 is 4246602402.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 20420664198 and 20420664207.

It is not an unprimeable number, because it can be changed into a prime (20420664247) 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, 42542811 + ... + 42543290.

Almost surely, 2^20420664240 is an apocalyptic number.

20420664240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20420664240 is an abundant number, since it is smaller than the sum of its proper divisors (42883395648).

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

20420664240 is a wasteful number, since it uses less digits than its factorization.

20420664240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85086117 (or 85086111 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 30.

The spelling of 20420664240 in words is "twenty billion, four hundred twenty million, six hundred sixty-four thousand, two hundred forty".