21020121232 has 20 divisors (see below), whose sum is σ = 44428892976. Its totient is φ = 9554600480.

The previous prime is 21020121229. The next prime is 21020121263. The reversal of 21020121232 is 23212102012.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (16).

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, 59716078 + ... + 59716429.

Almost surely, 2^21020121232 is an apocalyptic number.

21020121232 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21020121232 is an abundant number, since it is smaller than the sum of its proper divisors (23408771744).

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

21020121232 is a wasteful number, since it uses less digits than its factorization.

21020121232 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 119432526 (or 119432520 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 16.

Adding to 21020121232 its reverse (23212102012), we get a palindrome (44232223244).

The spelling of 21020121232 in words is "twenty-one billion, twenty million, one hundred twenty-one thousand, two hundred thirty-two".