1221242440 has 32 divisors (see below), whose sum is σ = 2997596160. Its totient is φ = 444088000.

The previous prime is 1221242411. The next prime is 1221242453. The reversal of 1221242440 is 442421221.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 1387336 + ... + 1388215.

It is an arithmetic number, because the mean of its divisors is an integer number (93674880).

Almost surely, 2^1221242440 is an apocalyptic number.

1221242440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221242440 is an abundant number, since it is smaller than the sum of its proper divisors (1776353720).

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

1221242440 is a wasteful number, since it uses less digits than its factorization.

1221242440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2775573 (or 2775569 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 22.

The square root of 1221242440 is about 34946.2793441591. The cubic root of 1221242440 is about 1068.8923349754.

Adding to 1221242440 its reverse (442421221), we get a palindrome (1663663661).

The spelling of 1221242440 in words is "one billion, two hundred twenty-one million, two hundred forty-two thousand, four hundred forty".