21244040420 has 24 divisors (see below), whose sum is σ = 45561688704. Its totient is φ = 8316815456.

The previous prime is 21244040401. The next prime is 21244040423. The reversal of 21244040420 is 2404044212.

It is not an unprimeable number, because it can be changed into a prime (21244040423) 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, 11299082 + ... + 11300961.

It is an arithmetic number, because the mean of its divisors is an integer number (1898403696).

Almost surely, 2^21244040420 is an apocalyptic number.

21244040420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21244040420 is an abundant number, since it is smaller than the sum of its proper divisors (24317648284).

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

21244040420 is a wasteful number, since it uses less digits than its factorization.

21244040420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22600099 (or 22600097 counting only the distinct ones).

The product of its (nonzero) digits is 2048, while the sum is 23.

Adding to 21244040420 its reverse (2404044212), we get a palindrome (23648084632).

The spelling of 21244040420 in words is "twenty-one billion, two hundred forty-four million, forty thousand, four hundred twenty".