1220321540 has 48 divisors (see below), whose sum is σ = 2779633584. Its totient is φ = 448204800.

The previous prime is 1220321539. The next prime is 1220321549. The reversal of 1220321540 is 451230221.

It can be written as a sum of positive squares in 8 ways, for example, as 65545216 + 1154776324 = 8096^2 + 33982^2 .

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 (1220321549) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 29831 + ... + 57710.

It is an arithmetic number, because the mean of its divisors is an integer number (57909033).

Almost surely, 2^1220321540 is an apocalyptic number.

1220321540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1220321540 is an abundant number, since it is smaller than the sum of its proper divisors (1559312044).

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

1220321540 is a wasteful number, since it uses less digits than its factorization.

1220321540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87608 (or 87606 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 1220321540 is about 34933.1009216187. The cubic root of 1220321540 is about 1068.6235948674.

Adding to 1220321540 its reverse (451230221), we get a palindrome (1671551761).

The spelling of 1220321540 in words is "one billion, two hundred twenty million, three hundred twenty-one thousand, five hundred forty".