31521345240 has 384 divisors, whose sum is σ = 122568422400. Its totient is φ = 6409912320.

The previous prime is 31521345223. The next prime is 31521345253. The reversal of 31521345240 is 4254312513.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 31521345198 and 31521345207.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 3034776 + ... + 3045144.

It is an arithmetic number, because the mean of its divisors is an integer number (319188600).

Almost surely, 2^31521345240 is an apocalyptic number.

31521345240 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 31521345240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (61284211200).

31521345240 is an abundant number, since it is smaller than the sum of its proper divisors (91047077160).

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

31521345240 is a wasteful number, since it uses less digits than its factorization.

31521345240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10455 (or 10444 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 30.

Adding to 31521345240 its reverse (4254312513), we get a palindrome (35775657753).

The spelling of 31521345240 in words is "thirty-one billion, five hundred twenty-one million, three hundred forty-five thousand, two hundred forty".