221652540 has 72 divisors (see below), whose sum is σ = 673611120. Its totient is φ = 58996224.

The previous prime is 221652527. The next prime is 221652547. The reversal of 221652540 is 45256122.

221652540 is a `hidden beast` number, since 2 + 2 + 1 + 652 + 5 + 4 + 0 = 666.

221652540 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a zygodrome in base 6.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221652547) 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, 148116 + ... + 149604.

It is an arithmetic number, because the mean of its divisors is an integer number (9355710).

Almost surely, 2^221652540 is an apocalyptic number.

221652540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221652540 is an abundant number, since it is smaller than the sum of its proper divisors (451958580).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

221652540 is a wasteful number, since it uses less digits than its factorization.

221652540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2331 (or 2326 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 27.

The square root of 221652540 is about 14887.9998656636. Note that the first 3 decimals coincide. The cubic root of 221652540 is about 605.1888307044.

It can be divided in two parts, 2216525 and 40, that added together give a triangular number (2216565 = T₂₁₀₅).

The spelling of 221652540 in words is "two hundred twenty-one million, six hundred fifty-two thousand, five hundred forty".