1221420240 has 60 divisors (see below), whose sum is σ = 4101938724. Its totient is φ = 325711872.

The previous prime is 1221420229. The next prime is 1221420271. The reversal of 1221420240 is 420241221.

1221420240 is a `hidden beast` number, since 1 + 2 + 2 + 1 + 420 + 240 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 518746176 + 702674064 = 22776^2 + 26508^2 .

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

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 11 ways as a sum of consecutive naturals, for example, 847489 + ... + 848928.

Almost surely, 2^1221420240 is an apocalyptic number.

1221420240 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221420240 is an abundant number, since it is smaller than the sum of its proper divisors (2880518484).

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

1221420240 is a wasteful number, since it uses less digits than its factorization.

1221420240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1696436 (or 1696427 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

The square root of 1221420240 is about 34948.8231561522. The cubic root of 1221420240 is about 1068.9442056028.

Adding to 1221420240 its reverse (420241221), we get a palindrome (1641661461).

The spelling of 1221420240 in words is "one billion, two hundred twenty-one million, four hundred twenty thousand, two hundred forty".