21002051420 has 48 divisors (see below), whose sum is σ = 50426136768. Its totient is φ = 7197672960.

The previous prime is 21002051419. The next prime is 21002051423. The reversal of 21002051420 is 2415020012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002051423) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 315890 + ... + 376550.

It is an arithmetic number, because the mean of its divisors is an integer number (1050544516).

Almost surely, 2^21002051420 is an apocalyptic number.

21002051420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21002051420 is an abundant number, since it is smaller than the sum of its proper divisors (29424085348).

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

21002051420 is a wasteful number, since it uses less digits than its factorization.

21002051420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63150 (or 63148 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 17.

Adding to 21002051420 its reverse (2415020012), we get a palindrome (23417071432).

The spelling of 21002051420 in words is "twenty-one billion, two million, fifty-one thousand, four hundred twenty".