21053404420 has 24 divisors (see below), whose sum is σ = 44227744344. Its totient is φ = 8418391296.

The previous prime is 21053404403. The next prime is 21053404481. The reversal of 21053404420 is 2440435012.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 10830981184 + 10222423236 = 104072^2 + 101106^2 .

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, 127087 + ... + 241366.

It is an arithmetic number, because the mean of its divisors is an integer number (1842822681).

Almost surely, 2^21053404420 is an apocalyptic number.

21053404420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21053404420 is an abundant number, since it is smaller than the sum of its proper divisors (23174339924).

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

21053404420 is a wasteful number, since it uses less digits than its factorization.

21053404420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 371319 (or 371317 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 25.

Adding to 21053404420 its reverse (2440435012), we get a palindrome (23493839432).

The spelling of 21053404420 in words is "twenty-one billion, fifty-three million, four hundred four thousand, four hundred twenty".