221525145 has 16 divisors (see below), whose sum is σ = 393822720. Its totient is φ = 118146672.

The previous prime is 221525131. The next prime is 221525153. The reversal of 221525145 is 541525122.

It is not a de Polignac number, because 221525145 - 2¹² = 221521049 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 820329 + ... + 820598.

It is an arithmetic number, because the mean of its divisors is an integer number (24613920).

Almost surely, 2^221525145 is an apocalyptic number.

It is an amenable number.

221525145 is a deficient number, since it is larger than the sum of its proper divisors (172297575).

221525145 is a wasteful number, since it uses less digits than its factorization.

221525145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1640941 (or 1640935 counting only the distinct ones).

The product of its digits is 4000, while the sum is 27.

The square root of 221525145 is about 14883.7208049600. The cubic root of 221525145 is about 605.0728642064.

The spelling of 221525145 in words is "two hundred twenty-one million, five hundred twenty-five thousand, one hundred forty-five".