21231202509 has 24 divisors (see below), whose sum is σ = 35216032800. Its totient is φ = 12190163040.

The previous prime is 21231202481. The next prime is 21231202529. The reversal of 21231202509 is 90520213212.

It is a happy number.

It is not a de Polignac number, because 21231202509 - 2⁷ = 21231202381 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21231202529) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 5641714 + ... + 5645475.

It is an arithmetic number, because the mean of its divisors is an integer number (1467334700).

Almost surely, 2^21231202509 is an apocalyptic number.

It is an amenable number.

21231202509 is a deficient number, since it is larger than the sum of its proper divisors (13984830291).

21231202509 is a wasteful number, since it uses less digits than its factorization.

21231202509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11287225 (or 11287222 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The spelling of 21231202509 in words is "twenty-one billion, two hundred thirty-one million, two hundred two thousand, five hundred nine".