1221415725 has 48 divisors (see below), whose sum is σ = 2049583104. Its totient is φ = 641760000.

The previous prime is 1221415721. The next prime is 1221415753. The reversal of 1221415725 is 5275141221.

It is a happy number.

It is not a de Polignac number, because 1221415725 - 2² = 1221415721 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1221415692 and 1221415701.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221415721) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2901015 + ... + 2901435.

It is an arithmetic number, because the mean of its divisors is an integer number (42699648).

Almost surely, 2^1221415725 is an apocalyptic number.

1221415725 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1221415725 is a deficient number, since it is larger than the sum of its proper divisors (828167379).

1221415725 is a wasteful number, since it uses less digits than its factorization.

1221415725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 918 (or 913 counting only the distinct ones).

The product of its digits is 5600, while the sum is 30.

The square root of 1221415725 is about 34948.7585616428. The cubic root of 1221415725 is about 1068.9428884779.

Adding to 1221415725 its reverse (5275141221), we get a palindrome (6496556946).

The spelling of 1221415725 in words is "one billion, two hundred twenty-one million, four hundred fifteen thousand, seven hundred twenty-five".