1221525 has 36 divisors (see below), whose sum is σ = 2248740. Its totient is φ = 633600.

The previous prime is 1221523. The next prime is 1221527. The reversal of 1221525 is 5251221.

It is an interprime number because it is at equal distance from previous prime (1221523) and next prime (1221527).

It can be written as a sum of positive squares in 6 ways, for example, as 400689 + 820836 = 633^2 + 906^2 .

It is not a de Polignac number, because 1221525 - 2¹ = 1221523 is a prime.

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 1221498 and 1221507.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221523) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 13681 + ... + 13769.

It is an arithmetic number, because the mean of its divisors is an integer number (62465).

2^1221525 is an apocalyptic number.

1221525 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1221525 is a deficient number, since it is larger than the sum of its proper divisors (1027215).

1221525 is a wasteful number, since it uses less digits than its factorization.

1221525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166 (or 158 counting only the distinct ones).

The product of its digits is 200, while the sum is 18.

The square root of 1221525 is about 1105.2262211873. The cubic root of 1221525 is about 106.8974765490.

Adding to 1221525 its reverse (5251221), we get a palindrome (6472746).

The spelling of 1221525 in words is "one million, two hundred twenty-one thousand, five hundred twenty-five".