1221551325 has 72 divisors (see below), whose sum is σ = 2332886400. Its totient is φ = 609223680.

The previous prime is 1221551323. The next prime is 1221551333. The reversal of 1221551325 is 5231551221.

1221551325 is a `hidden beast` number, since 122 + 1 + 5 + 513 + 25 = 666.

It is not a de Polignac number, because 1221551325 - 2¹ = 1221551323 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221551323) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 335917 + ... + 339533.

It is an arithmetic number, because the mean of its divisors is an integer number (32401200).

Almost surely, 2^1221551325 is an apocalyptic number.

1221551325 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1221551325 is a deficient number, since it is larger than the sum of its proper divisors (1111335075).

1221551325 is a wasteful number, since it uses less digits than its factorization.

1221551325 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3731 (or 3723 counting only the distinct ones).

The product of its digits is 3000, while the sum is 27.

The square root of 1221551325 is about 34950.6984908743. The cubic root of 1221551325 is about 1068.9824445682.

The spelling of 1221551325 in words is "one billion, two hundred twenty-one million, five hundred fifty-one thousand, three hundred twenty-five".