221031400 has 24 divisors (see below), whose sum is σ = 513898470. Its totient is φ = 88412480.

The previous prime is 221031397. The next prime is 221031409. The reversal of 221031400 is 4130122.

It can be written as a sum of positive squares in 3 ways, for example, as 94828644 + 126202756 = 9738^2 + 11234^2 .

It is not an unprimeable number, because it can be changed into a prime (221031409) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 552379 + ... + 552778.

Almost surely, 2^221031400 is an apocalyptic number.

221031400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221031400 is an abundant number, since it is smaller than the sum of its proper divisors (292867070).

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

221031400 is a wasteful number, since it uses less digits than its factorization.

221031400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1105173 (or 1105164 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 221031400 is about 14867.1248060948. The cubic root of 221031400 is about 604.6229921259.

Adding to 221031400 its reverse (4130122), we get a palindrome (225161522).

The spelling of 221031400 in words is "two hundred twenty-one million, thirty-one thousand, four hundred".