20501133440 has 64 divisors (see below), whose sum is σ = 49061885760. Its totient is φ = 8191859712.

The previous prime is 20501133431. The next prime is 20501133451. The reversal of 20501133440 is 4433110502.

It is a tau number, because it is divible by the number of its divisors (64).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 612827 + ... + 645413.

It is an arithmetic number, because the mean of its divisors is an integer number (766591965).

Almost surely, 2^20501133440 is an apocalyptic number.

20501133440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20501133440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24530942880).

20501133440 is an abundant number, since it is smaller than the sum of its proper divisors (28560752320).

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

20501133440 is an equidigital number, since it uses as much as digits as its factorization.

20501133440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33589 (or 33577 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 23.

Adding to 20501133440 its reverse (4433110502), we get a palindrome (24934243942).

The spelling of 20501133440 in words is "twenty billion, five hundred one million, one hundred thirty-three thousand, four hundred forty".