1221043240 has 16 divisors (see below), whose sum is σ = 2747347380. Its totient is φ = 488417280.

The previous prime is 1221043223. The next prime is 1221043247. The reversal of 1221043240 is 423401221.

It can be written as a sum of positive squares in 2 ways, for example, as 1194808356 + 26234884 = 34566^2 + 5122^2 .

It is not an unprimeable number, because it can be changed into a prime (1221043247) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15263001 + ... + 15263080.

Almost surely, 2^1221043240 is an apocalyptic number.

1221043240 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221043240 is an abundant number, since it is smaller than the sum of its proper divisors (1526304140).

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

1221043240 is a wasteful number, since it uses less digits than its factorization.

1221043240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30526092 (or 30526088 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 19.

The square root of 1221043240 is about 34943.4291391100. The cubic root of 1221043240 is about 1068.8342152213.

Adding to 1221043240 its reverse (423401221), we get a palindrome (1644444461).

The spelling of 1221043240 in words is "one billion, two hundred twenty-one million, forty-three thousand, two hundred forty".