221005525 has 54 divisors (see below), whose sum is σ = 316973202. Its totient is φ = 152755200.

The previous prime is 221005517. The next prime is 221005553. The reversal of 221005525 is 525500122.

221005525 = T₄₇₈ + T₄₇₉ + ... + T₁₁₂₇.

221005525 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 27 ways, for example, as 213568996 + 7436529 = 14614^2 + 2727^2 .

It is not a de Polignac number, because 221005525 - 2³ = 221005517 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 221005496 and 221005505.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 53 ways as a sum of consecutive naturals, for example, 1220935 + ... + 1221115.

Almost surely, 2^221005525 is an apocalyptic number.

221005525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

221005525 is a deficient number, since it is larger than the sum of its proper divisors (95967677).

221005525 is a wasteful number, since it uses less digits than its factorization.

221005525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 251 (or 216 counting only the distinct ones).

The product of its (nonzero) digits is 1000, while the sum is 22.

The square root of 221005525 is about 14866.2545720164. The cubic root of 221005525 is about 604.5993978456.

Adding to 221005525 its reverse (525500122), we get a palindrome (746505647).

It can be divided in two parts, 22100 and 5525, that multiplied together give a square (122102500 = 11050²).

The spelling of 221005525 in words is "two hundred twenty-one million, five thousand, five hundred twenty-five".