1221222440 has 32 divisors (see below), whose sum is σ = 2792801160. Its totient is φ = 480480000.

The previous prime is 1221222439. The next prime is 1221222461. The reversal of 1221222440 is 442221221.

It can be written as a sum of positive squares in 4 ways, for example, as 736253956 + 484968484 = 27134^2 + 22022^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 247811 + ... + 252690.

Almost surely, 2^1221222440 is an apocalyptic number.

1221222440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221222440 is an abundant number, since it is smaller than the sum of its proper divisors (1571578720).

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

1221222440 is a wasteful number, since it uses less digits than its factorization.

1221222440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 500573 (or 500569 counting only the distinct ones).

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

The square root of 1221222440 is about 34945.9931894917. The cubic root of 1221222440 is about 1068.8864999442.

Adding to 1221222440 its reverse (442221221), we get a palindrome (1663443661).

The spelling of 1221222440 in words is "one billion, two hundred twenty-one million, two hundred twenty-two thousand, four hundred forty".