21244020140 has 48 divisors (see below), whose sum is σ = 52171375872. Its totient is φ = 7114274496.

The previous prime is 21244020139. The next prime is 21244020143. The reversal of 21244020140 is 4102044212.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is not an unprimeable number, because it can be changed into a prime (21244020143) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1758434 + ... + 1770473.

It is an arithmetic number, because the mean of its divisors is an integer number (1086903664).

Almost surely, 2^21244020140 is an apocalyptic number.

21244020140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21244020140 is an abundant number, since it is smaller than the sum of its proper divisors (30927355732).

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

21244020140 is a wasteful number, since it uses less digits than its factorization.

21244020140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3528966 (or 3528964 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 20.

Adding to 21244020140 its reverse (4102044212), we get a palindrome (25346064352).

The spelling of 21244020140 in words is "twenty-one billion, two hundred forty-four million, twenty thousand, one hundred forty".