21024004420 has 12 divisors (see below), whose sum is σ = 44150409324. Its totient is φ = 8409601760.

The previous prime is 21024004283. The next prime is 21024004439. The reversal of 21024004420 is 2440042012.

It can be written as a sum of positive squares in 2 ways, for example, as 3846232324 + 17177772096 = 62018^2 + 131064^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 525600091 + ... + 525600130.

It is an arithmetic number, because the mean of its divisors is an integer number (3679200777).

Almost surely, 2^21024004420 is an apocalyptic number.

21024004420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21024004420 is an abundant number, since it is smaller than the sum of its proper divisors (23126404904).

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

21024004420 is a wasteful number, since it uses less digits than its factorization.

21024004420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1051200230 (or 1051200228 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 19.

Adding to 21024004420 its reverse (2440042012), we get a palindrome (23464046432).

The spelling of 21024004420 in words is "twenty-one billion, twenty-four million, four thousand, four hundred twenty".