21203031172 has 24 divisors (see below), whose sum is σ = 37445990400. Its totient is φ = 10504238976.

The previous prime is 21203031169. The next prime is 21203031173. The reversal of 21203031172 is 27113030212.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21203031173) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1874229 + ... + 1885507.

It is an arithmetic number, because the mean of its divisors is an integer number (1560249600).

Almost surely, 2^21203031172 is an apocalyptic number.

It is an amenable number.

21203031172 is a deficient number, since it is larger than the sum of its proper divisors (16242959228).

21203031172 is a wasteful number, since it uses less digits than its factorization.

21203031172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15555 (or 15553 counting only the distinct ones).

The product of its (nonzero) digits is 504, while the sum is 22.

Adding to 21203031172 its reverse (27113030212), we get a palindrome (48316061384).

The spelling of 21203031172 in words is "twenty-one billion, two hundred three million, thirty-one thousand, one hundred seventy-two".