1221440440 has 32 divisors (see below), whose sum is σ = 2998082160. Its totient is φ = 444160000.

The previous prime is 1221440431. The next prime is 1221440443. The reversal of 1221440440 is 440441221.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221440443) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1387561 + ... + 1388440.

Almost surely, 2^1221440440 is an apocalyptic number.

1221440440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221440440 is an abundant number, since it is smaller than the sum of its proper divisors (1776641720).

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

1221440440 is a wasteful number, since it uses less digits than its factorization.

1221440440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2776023 (or 2776019 counting only the distinct ones).

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

The square root of 1221440440 is about 34949.1121489517. The cubic root of 1221440440 is about 1068.9500983478.

Adding to 1221440440 its reverse (440441221), we get a palindrome (1661881661).

The spelling of 1221440440 in words is "one billion, two hundred twenty-one million, four hundred forty thousand, four hundred forty".