1221326145 has 48 divisors (see below), whose sum is σ = 2284066512. Its totient is φ = 600145920.

The previous prime is 1221326069. The next prime is 1221326153. The reversal of 1221326145 is 5416231221.

1221326145 is a `hidden beast` number, since 12 + 2 + 1 + 32 + 614 + 5 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 33558849 + 1187767296 = 5793^2 + 34464^2 .

It is not a de Polignac number, because 1221326145 - 2¹⁸ = 1221064001 is a prime.

It is a super-2 number, since 2×1221326145² = 2983275104921122050, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 373357 + ... + 376613.

It is an arithmetic number, because the mean of its divisors is an integer number (47584719).

Almost surely, 2^1221326145 is an apocalyptic number.

1221326145 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1221326145 is a deficient number, since it is larger than the sum of its proper divisors (1062740367).

1221326145 is a wasteful number, since it uses less digits than its factorization.

1221326145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3922 (or 3919 counting only the distinct ones).

The product of its digits is 2880, while the sum is 27.

The square root of 1221326145 is about 34947.4769475566. The cubic root of 1221326145 is about 1068.9167553487.

Adding to 1221326145 its reverse (5416231221), we get a palindrome (6637557366).

The spelling of 1221326145 in words is "one billion, two hundred twenty-one million, three hundred twenty-six thousand, one hundred forty-five".