20401320040 has 16 divisors (see below), whose sum is σ = 45902970180. Its totient is φ = 8160528000.

The previous prime is 20401320019. The next prime is 20401320041. The reversal of 20401320040 is 4002310402.

It can be written as a sum of positive squares in 2 ways, for example, as 18834268644 + 1567051396 = 137238^2 + 39586^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20401319996 and 20401320023.

It is not an unprimeable number, because it can be changed into a prime (20401320041) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 255016461 + ... + 255016540.

Almost surely, 2^20401320040 is an apocalyptic number.

20401320040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20401320040 is an abundant number, since it is smaller than the sum of its proper divisors (25501650140).

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

20401320040 is a wasteful number, since it uses less digits than its factorization.

20401320040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 510033012 (or 510033008 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 16.

Adding to 20401320040 its reverse (4002310402), we get a palindrome (24403630442).

The spelling of 20401320040 in words is "twenty billion, four hundred one million, three hundred twenty thousand, forty".