31221030100 has 108 divisors (see below), whose sum is σ = 73459441524. Its totient is φ = 11449451520.

The previous prime is 31221030079. The next prime is 31221030101. The reversal of 31221030100 is 103012213.

It can be written as a sum of positive squares in 18 ways, for example, as 29129614276 + 2091415824 = 170674^2 + 45732^2 .

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31221030101) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 99747544 + ... + 99747856.

Almost surely, 2^31221030100 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31221030100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36729720762).

31221030100 is an abundant number, since it is smaller than the sum of its proper divisors (42238411424).

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

31221030100 is a wasteful number, since it uses less digits than its factorization.

31221030100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 894 (or 610 counting only the distinct ones).

The product of its (nonzero) digits is 36, while the sum is 13.

Adding to 31221030100 its reverse (103012213), we get a palindrome (31324042313).

The spelling of 31221030100 in words is "thirty-one billion, two hundred twenty-one million, thirty thousand, one hundred".