31280420 has 24 divisors (see below), whose sum is σ = 66059448. Its totient is φ = 12441600.

The previous prime is 31280419. The next prime is 31280423. The reversal of 31280420 is 2408213.

It can be written as a sum of positive squares in 4 ways, for example, as 3232804 + 28047616 = 1798^2 + 5296^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 31280392 and 31280401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31280423) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 701 + ... + 7940.

It is an arithmetic number, because the mean of its divisors is an integer number (2752477).

Almost surely, 2^31280420 is an apocalyptic number.

It is an amenable number.

31280420 is an abundant number, since it is smaller than the sum of its proper divisors (34779028).

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

31280420 is a wasteful number, since it uses less digits than its factorization.

31280420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8831 (or 8829 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 31280420 is about 5592.8901294411. The cubic root of 31280420 is about 315.0824341238.

Adding to 31280420 its reverse (2408213), we get a palindrome (33688633).

The spelling of 31280420 in words is "thirty-one million, two hundred eighty thousand, four hundred twenty".