1221424040 has 32 divisors (see below), whose sum is σ = 2749799880. Its totient is φ = 488285952.

The previous prime is 1221424033. The next prime is 1221424049. The reversal of 1221424040 is 404241221.

It can be written as a sum of positive squares in 4 ways, for example, as 1145280964 + 76143076 = 33842^2 + 8726^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is not an unprimeable number, because it can be changed into a prime (1221424049) 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, 69422 + ... + 85218.

Almost surely, 2^1221424040 is an apocalyptic number.

1221424040 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221424040 is an abundant number, since it is smaller than the sum of its proper divisors (1528375840).

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

1221424040 is a wasteful number, since it uses less digits than its factorization.

1221424040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17741 (or 17737 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 20.

The square root of 1221424040 is about 34948.8775213168. The cubic root of 1221424040 is about 1068.9453141440.

Adding to 1221424040 its reverse (404241221), we get a palindrome (1625665261).

The spelling of 1221424040 in words is "one billion, two hundred twenty-one million, four hundred twenty-four thousand, forty".