21002333431 has 4 divisors (see below), whose sum is σ = 21019150000. Its totient is φ = 20985516864.

The previous prime is 21002333399. The next prime is 21002333483. The reversal of 21002333431 is 13433320012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21002333431 - 2⁵ = 21002333399 is a prime.

It is a super-2 number, since 2×21002333431² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002331431) 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, 8406411 + ... + 8408908.

It is an arithmetic number, because the mean of its divisors is an integer number (5254787500).

Almost surely, 2^21002333431 is an apocalyptic number.

21002333431 is a deficient number, since it is larger than the sum of its proper divisors (16816569).

21002333431 is a wasteful number, since it uses less digits than its factorization.

21002333431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16816568.

The product of its (nonzero) digits is 1296, while the sum is 22.

Adding to 21002333431 its reverse (13433320012), we get a palindrome (34435653443).

The spelling of 21002333431 in words is "twenty-one billion, two million, three hundred thirty-three thousand, four hundred thirty-one".