1221451225 has 24 divisors (see below), whose sum is σ = 1582791552. Its totient is φ = 933292800.

The previous prime is 1221451177. The next prime is 1221451229. The reversal of 1221451225 is 5221541221.

It is a de Polignac number, because none of the positive numbers 2^k-1221451225 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a self number, because there is not a number n which added to its sum of digits gives 1221451225.

It is not an unprimeable number, because it can be changed into a prime (1221451229) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 564145 + ... + 566305.

It is an arithmetic number, because the mean of its divisors is an integer number (65949648).

Almost surely, 2^1221451225 is an apocalyptic number.

It is an amenable number.

1221451225 is a deficient number, since it is larger than the sum of its proper divisors (361340327).

1221451225 is a wasteful number, since it uses less digits than its factorization.

1221451225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3177 (or 3172 counting only the distinct ones).

The product of its digits is 1600, while the sum is 25.

The square root of 1221451225 is about 34949.2664443762. The cubic root of 1221451225 is about 1068.9532445219.

Adding to 1221451225 its reverse (5221541221), we get a palindrome (6442992446).

The spelling of 1221451225 in words is "one billion, two hundred twenty-one million, four hundred fifty-one thousand, two hundred twenty-five".