7525111221 has 8 divisors (see below), whose sum is σ = 11148312960. Its totient is φ = 5016740796.

The previous prime is 7525111169. The next prime is 7525111229. The reversal of 7525111221 is 1221115257.

7525111221 is a `hidden beast` number, since 7 + 525 + 1 + 112 + 21 = 666.

It is not a de Polignac number, because 7525111221 - 2⁹ = 7525110709 is a prime.

It is a super-2 number, since 2×7525111221² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 278707823 = 7525111221 / (7 + 5 + 2 + 5 + 1 + 1 + 1 + 2 + 2 + 1).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7525111229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 139353885 + ... + 139353938.

It is an arithmetic number, because the mean of its divisors is an integer number (1393539120).

Almost surely, 2^7525111221 is an apocalyptic number.

It is an amenable number.

7525111221 is a deficient number, since it is larger than the sum of its proper divisors (3623201739).

7525111221 is a wasteful number, since it uses less digits than its factorization.

7525111221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 278707832 (or 278707826 counting only the distinct ones).

The product of its digits is 1400, while the sum is 27.

The square root of 7525111221 is about 86747.3989293051. The cubic root of 7525111221 is about 1959.6159893419.

Adding to 7525111221 its reverse (1221115257), we get a palindrome (8746226478).

The spelling of 7525111221 in words is "seven billion, five hundred twenty-five million, one hundred eleven thousand, two hundred twenty-one".