21001001232 has 20 divisors (see below), whose sum is σ = 54252586640. Its totient is φ = 7000333728.

The previous prime is 21001001227. The next prime is 21001001239. The reversal of 21001001232 is 23210010012.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is not an unprimeable number, because it can be changed into a prime (21001001239) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 218760382 + ... + 218760477.

It is an arithmetic number, because the mean of its divisors is an integer number (2712629332).

Almost surely, 2^21001001232 is an apocalyptic number.

It is an amenable number.

21001001232 is an abundant number, since it is smaller than the sum of its proper divisors (33251585408).

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

21001001232 is a wasteful number, since it uses less digits than its factorization.

21001001232 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 437520870 (or 437520864 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 12.

Adding to 21001001232 its reverse (23210010012), we get a palindrome (44211011244).

The spelling of 21001001232 in words is "twenty-one billion, one million, one thousand, two hundred thirty-two".