31221216601 has 8 divisors (see below), whose sum is σ = 33225568200. Its totient is φ = 29235510528.

The previous prime is 31221216599. The next prime is 31221216619. The reversal of 31221216601 is 10661212213.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 24695808201 + 6525408400 = 157149^2 + 80780^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 31221216601 - 2¹ = 31221216599 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31221216001) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4657926 + ... + 4664623.

It is an arithmetic number, because the mean of its divisors is an integer number (4153196025).

Almost surely, 2^31221216601 is an apocalyptic number.

It is an amenable number.

31221216601 is a deficient number, since it is larger than the sum of its proper divisors (2004351599).

31221216601 is a wasteful number, since it uses less digits than its factorization.

31221216601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9322763.

The product of its (nonzero) digits is 864, while the sum is 25.

Adding to 31221216601 its reverse (10661212213), we get a palindrome (41882428814).

The spelling of 31221216601 in words is "thirty-one billion, two hundred twenty-one million, two hundred sixteen thousand, six hundred one".