21001233420 has 96 divisors (see below), whose sum is σ = 66257533440. Its totient is φ = 5521440960.

The previous prime is 21001233419. The next prime is 21001233437. The reversal of 21001233420 is 2433210012.

21001233420 is a `hidden beast` number, since 2 + 10 + 0 + 1 + 233 + 420 = 666.

It is a super-2 number, since 2×21001233420² (a number of 21 digits) contains 22 as substring.

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 = 21001233393 and 21001233402.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 235542 + ... + 312221.

It is an arithmetic number, because the mean of its divisors is an integer number (690182640).

Almost surely, 2^21001233420 is an apocalyptic number.

21001233420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21001233420 is an abundant number, since it is smaller than the sum of its proper divisors (45256300020).

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

21001233420 is a wasteful number, since it uses less digits than its factorization.

21001233420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 547852 (or 547844 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

Adding to 21001233420 its reverse (2433210012), we get a palindrome (23434443432).

The spelling of 21001233420 in words is "twenty-one billion, one million, two hundred thirty-three thousand, four hundred twenty".