264561921 has 12 divisors (see below), whose sum is σ = 411540948. Its totient is φ = 162807264.

The previous prime is 264561883. The next prime is 264561949. The reversal of 264561921 is 129165462.

264561921 is a `hidden beast` number, since 2 + 6 + 4 + 561 + 92 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 135489600 + 129072321 = 11640^2 + 11361^2 .

It is not a de Polignac number, because 264561921 - 2¹⁷ = 264430849 is a prime.

It is not an unprimeable number, because it can be changed into a prime (264561221) 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 11 ways as a sum of consecutive naturals, for example, 1130490 + ... + 1130723.

It is an arithmetic number, because the mean of its divisors is an integer number (34295079).

Almost surely, 2^264561921 is an apocalyptic number.

It is an amenable number.

264561921 is a deficient number, since it is larger than the sum of its proper divisors (146979027).

264561921 is a wasteful number, since it uses less digits than its factorization.

264561921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2261232 (or 2261229 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

The square root of 264561921 is about 16265.3595410615. The cubic root of 264561921 is about 641.9616901471.

The spelling of 264561921 in words is "two hundred sixty-four million, five hundred sixty-one thousand, nine hundred twenty-one".