20001215544 has 32 divisors (see below), whose sum is σ = 50102478720. Its totient is φ = 6653813216.

The previous prime is 20001215539. The next prime is 20001215567. The reversal of 20001215544 is 44551210002.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 816342 + ... + 840485.

It is an arithmetic number, because the mean of its divisors is an integer number (1565702460).

Almost surely, 2^20001215544 is an apocalyptic number.

20001215544 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

20001215544 is an abundant number, since it is smaller than the sum of its proper divisors (30101263176).

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

20001215544 is a wasteful number, since it uses less digits than its factorization.

20001215544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1657339 (or 1657335 counting only the distinct ones).

The product of its (nonzero) digits is 1600, while the sum is 24.

Adding to 20001215544 its reverse (44551210002), we get a palindrome (64552425546).

The spelling of 20001215544 in words is "twenty billion, one million, two hundred fifteen thousand, five hundred forty-four".