31223140 has 96 divisors (see below), whose sum is σ = 75569760. Its totient is φ = 10752000.

The previous prime is 31223131. The next prime is 31223141. The reversal of 31223140 is 4132213.

It is a happy number.

It can be written as a sum of positive squares in 16 ways, for example, as 11009124 + 20214016 = 3318^2 + 4496^2 .

It is not an unprimeable number, because it can be changed into a prime (31223141) 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, 309090 + ... + 309190.

It is an arithmetic number, because the mean of its divisors is an integer number (787185).

Almost surely, 2^31223140 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 31223140, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37784880).

31223140 is an abundant number, since it is smaller than the sum of its proper divisors (44346620).

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

31223140 is a wasteful number, since it uses less digits than its factorization.

31223140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 193 (or 191 counting only the distinct ones).

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

The square root of 31223140 is about 5587.7669958580. The cubic root of 31223140 is about 314.8899926608.

Adding to 31223140 its reverse (4132213), we get a palindrome (35355353).

It can be divided in two parts, 31 and 223140, that multiplied together give a triangular number (6917340 = T₃₇₁₉).

The spelling of 31223140 in words is "thirty-one million, two hundred twenty-three thousand, one hundred forty".