31221662220 has 720 divisors, whose sum is σ = 121616732160. Its totient is φ = 6666395904.

The previous prime is 31221662161. The next prime is 31221662249. The reversal of 31221662220 is 2226612213.

It is a happy number.

31221662220 is a `hidden beast` number, since 3 + 1 + 2 + 2 + 16 + 622 + 20 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 239 ways as a sum of consecutive naturals, for example, 191543859 + ... + 191544021.

It is an arithmetic number, because the mean of its divisors is an integer number (168912128).

Almost surely, 2^31221662220 is an apocalyptic number.

31221662220 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31221662220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (60808366080).

31221662220 is an abundant number, since it is smaller than the sum of its proper divisors (90395069940).

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

31221662220 is a wasteful number, since it uses less digits than its factorization.

31221662220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 344 (or 326 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The spelling of 31221662220 in words is "thirty-one billion, two hundred twenty-one million, six hundred sixty-two thousand, two hundred twenty".