31221450 has 120 divisors (see below), whose sum is σ = 93579948. Its totient is φ = 7672320.

The previous prime is 31221431. The next prime is 31221457. The reversal of 31221450 is 5412213.

It can be written as a sum of positive squares in 6 ways, for example, as 7338681 + 23882769 = 2709^2 + 4887^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (31221457) by changing a digit.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 52354 + ... + 52946.

Almost surely, 2^31221450 is an apocalyptic number.

31221450 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 31221450, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (46789974).

31221450 is an abundant number, since it is smaller than the sum of its proper divisors (62358498).

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

31221450 is a wasteful number, since it uses less digits than its factorization.

31221450 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 630 (or 616 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 31221450 is about 5587.6157706127. The cubic root of 31221450 is about 314.8843112582.

Adding to 31221450 its reverse (5412213), we get a palindrome (36633663).

The spelling of 31221450 in words is "thirty-one million, two hundred twenty-one thousand, four hundred fifty".