31220205140 has 24 divisors (see below), whose sum is σ = 65566133640. Its totient is φ = 12487376768.

The previous prime is 31220205109. The next prime is 31220205151. The reversal of 31220205140 is 4150202213.

It can be written as a sum of positive squares in 4 ways, for example, as 118766404 + 31101438736 = 10898^2 + 176356^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is an unprimeable number.

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, 458846 + ... + 522474.

It is an arithmetic number, because the mean of its divisors is an integer number (2731922235).

Almost surely, 2^31220205140 is an apocalyptic number.

It is an amenable number.

31220205140 is an abundant number, since it is smaller than the sum of its proper divisors (34345928500).

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

31220205140 is a wasteful number, since it uses less digits than its factorization.

31220205140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 88171 (or 88169 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 20.

Adding to 31220205140 its reverse (4150202213), we get a palindrome (35370407353).

The spelling of 31220205140 in words is "thirty-one billion, two hundred twenty million, two hundred five thousand, one hundred forty".