245665521 has 16 divisors (see below), whose sum is σ = 385358400. Its totient is φ = 154142784.

The previous prime is 245665499. The next prime is 245665561. The reversal of 245665521 is 125566542.

245665521 is a `hidden beast` number, since 2 + 45 + 66 + 552 + 1 = 666.

It is not a de Polignac number, because 245665521 - 2⁵ = 245665489 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (245665561) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 267151 + ... + 268068.

It is an arithmetic number, because the mean of its divisors is an integer number (24084900).

Almost surely, 2^245665521 is an apocalyptic number.

It is an amenable number.

245665521 is a deficient number, since it is larger than the sum of its proper divisors (139692879).

245665521 is a wasteful number, since it uses less digits than its factorization.

245665521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 535245 (or 535239 counting only the distinct ones).

The product of its digits is 72000, while the sum is 36.

The square root of 245665521 is about 15673.7207133469. The cubic root of 245665521 is about 626.2985447686.

The spelling of 245665521 in words is "two hundred forty-five million, six hundred sixty-five thousand, five hundred twenty-one".