31440220420 has 96 divisors (see below), whose sum is σ = 77626708992. Its totient is φ = 10472844288.

The previous prime is 31440220403. The next prime is 31440220421. The reversal of 31440220420 is 2402204413.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 31440220391 and 31440220400.

It is not an unprimeable number, because it can be changed into a prime (31440220421) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 884022 + ... + 918898.

It is an arithmetic number, because the mean of its divisors is an integer number (808611552).

Almost surely, 2^31440220420 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 31440220420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38813354496).

31440220420 is an abundant number, since it is smaller than the sum of its proper divisors (46186488572).

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

31440220420 is a wasteful number, since it uses less digits than its factorization.

31440220420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35077 (or 35075 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 22.

Adding to 31440220420 its reverse (2402204413), we get a palindrome (33842424833).

The spelling of 31440220420 in words is "thirty-one billion, four hundred forty million, two hundred twenty thousand, four hundred twenty".