21420135120 has 80 divisors (see below), whose sum is σ = 68022021312. Its totient is φ = 5572715520.

The previous prime is 21420135101. The next prime is 21420135137. The reversal of 21420135120 is 2153102412.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1078582 + ... + 1098261.

Almost surely, 2^21420135120 is an apocalyptic number.

21420135120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21420135120 is an abundant number, since it is smaller than the sum of its proper divisors (46601886192).

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

21420135120 is a wasteful number, since it uses less digits than its factorization.

21420135120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2176900 (or 2176894 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 21.

Adding to 21420135120 its reverse (2153102412), we get a palindrome (23573237532).

The spelling of 21420135120 in words is "twenty-one billion, four hundred twenty million, one hundred thirty-five thousand, one hundred twenty".