21172222506 has 32 divisors (see below), whose sum is σ = 42496272000. Its totient is φ = 7032133440.

The previous prime is 21172222483. The next prime is 21172222517. The reversal of 21172222506 is 60522227112.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3931936 + ... + 3937316.

It is an arithmetic number, because the mean of its divisors is an integer number (1328008500).

Almost surely, 2^21172222506 is an apocalyptic number.

21172222506 is an abundant number, since it is smaller than the sum of its proper divisors (21324049494).

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

21172222506 is a wasteful number, since it uses less digits than its factorization.

21172222506 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7614.

The product of its (nonzero) digits is 6720, while the sum is 30.

Adding to 21172222506 its reverse (60522227112), we get a palindrome (81694449618).

The spelling of 21172222506 in words is "twenty-one billion, one hundred seventy-two million, two hundred twenty-two thousand, five hundred six".