249991220 has 12 divisors (see below), whose sum is σ = 524981604. Its totient is φ = 99996480.

The previous prime is 249991211. The next prime is 249991229. The reversal of 249991220 is 22199942.

It is an interprime number because it is at equal distance from previous prime (249991211) and next prime (249991229).

It can be written as a sum of positive squares in 2 ways, for example, as 141039376 + 108951844 = 11876^2 + 10438^2 .

It is a super-2 number, since 2×249991220² = 124991220154176800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (249991229) 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 3 ways as a sum of consecutive naturals, for example, 6249761 + ... + 6249800.

It is an arithmetic number, because the mean of its divisors is an integer number (43748467).

Almost surely, 2^249991220 is an apocalyptic number.

249991220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

249991220 is an abundant number, since it is smaller than the sum of its proper divisors (274990384).

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

249991220 is a wasteful number, since it uses less digits than its factorization.

249991220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12499570 (or 12499568 counting only the distinct ones).

The product of its (nonzero) digits is 23328, while the sum is 38.

The square root of 249991220 is about 15811.1106504255. The cubic root of 249991220 is about 629.9531501232.

The spelling of 249991220 in words is "two hundred forty-nine million, nine hundred ninety-one thousand, two hundred twenty".