31531223240 has 128 divisors (see below), whose sum is σ = 80548473600. Its totient is φ = 11003489280.

The previous prime is 31531223233. The next prime is 31531223249. The reversal of 31531223240 is 4232213513.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (31531223249) 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, 2123522 + ... + 2138318.

It is an arithmetic number, because the mean of its divisors is an integer number (629284950).

Almost surely, 2^31531223240 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 31531223240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40274236800).

31531223240 is an abundant number, since it is smaller than the sum of its proper divisors (49017250360).

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

31531223240 is a wasteful number, since it uses less digits than its factorization.

31531223240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15015 (or 15011 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 26.

Adding to 31531223240 its reverse (4232213513), we get a palindrome (35763436753).

The spelling of 31531223240 in words is "thirty-one billion, five hundred thirty-one million, two hundred twenty-three thousand, two hundred forty".