21220302420 has 72 divisors (see below), whose sum is σ = 64525854120. Its totient is φ = 5644892160.

The previous prime is 21220302409. The next prime is 21220302449. The reversal of 21220302420 is 2420302212.

21220302420 is a `hidden beast` number, since 21 + 220 + 3 + 0 + 2 + 420 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 6893648784 + 14326653636 = 83028^2 + 119694^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21220302393 and 21220302402.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 70501 + ... + 217740.

Almost surely, 2^21220302420 is an apocalyptic number.

21220302420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21220302420 is an abundant number, since it is smaller than the sum of its proper divisors (43305551700).

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

21220302420 is a wasteful number, since it uses less digits than its factorization.

21220302420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 288665 (or 288660 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 18.

Adding to 21220302420 its reverse (2420302212), we get a palindrome (23640604632).

The spelling of 21220302420 in words is "twenty-one billion, two hundred twenty million, three hundred two thousand, four hundred twenty".