31421320 has 64 divisors (see below), whose sum is σ = 81285120. Its totient is φ = 10708224.

The previous prime is 31421311. The next prime is 31421329. The reversal of 31421320 is 2312413.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (31421311) and next prime (31421329).

It is a junction number, because it is equal to n+sod(n) for n = 31421294 and 31421303.

It is not an unprimeable number, because it can be changed into a prime (31421329) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 81849 + ... + 82231.

It is an arithmetic number, because the mean of its divisors is an integer number (1270080).

Almost surely, 2^31421320 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 31421320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40642560).

31421320 is an abundant number, since it is smaller than the sum of its proper divisors (49863800).

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

31421320 is a wasteful number, since it uses less digits than its factorization.

31421320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 694 (or 690 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 31421320 is about 5605.4723262184. The cubic root of 31421320 is about 315.5548129395.

Adding to 31421320 its reverse (2312413), we get a palindrome (33733733).

The spelling of 31421320 in words is "thirty-one million, four hundred twenty-one thousand, three hundred twenty".