31516420 has 48 divisors (see below), whose sum is σ = 72959040. Its totient is φ = 11362176.

The previous prime is 31516411. The next prime is 31516423. The reversal of 31516420 is 2461513.

It is a junction number, because it is equal to n+sod(n) for n = 31516391 and 31516400.

It is not an unprimeable number, because it can be changed into a prime (31516423) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9771 + ... + 12589.

It is an arithmetic number, because the mean of its divisors is an integer number (1519980).

Almost surely, 2^31516420 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 31516420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36479520).

31516420 is an abundant number, since it is smaller than the sum of its proper divisors (41442620).

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

31516420 is a wasteful number, since it uses less digits than its factorization.

31516420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2884 (or 2882 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 31516420 is about 5613.9486994450. The cubic root of 31516420 is about 315.8728458134.

Adding to 31516420 its reverse (2461513), we get a palindrome (33977933).

The spelling of 31516420 in words is "thirty-one million, five hundred sixteen thousand, four hundred twenty".