261921284 has 12 divisors (see below), whose sum is σ = 469542108. Its totient is φ = 127766400.

The previous prime is 261921281. The next prime is 261921287. The reversal of 261921284 is 482129162.

It is an interprime number because it is at equal distance from previous prime (261921281) and next prime (261921287).

It can be written as a sum of positive squares in 2 ways, for example, as 9746884 + 252174400 = 3122^2 + 15880^2 .

It is not an unprimeable number, because it can be changed into a prime (261921281) 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 3 ways as a sum of consecutive naturals, for example, 798377 + ... + 798704.

It is an arithmetic number, because the mean of its divisors is an integer number (39128509).

Almost surely, 2^261921284 is an apocalyptic number.

It is an amenable number.

261921284 is a deficient number, since it is larger than the sum of its proper divisors (207620824).

261921284 is a wasteful number, since it uses less digits than its factorization.

261921284 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1597126 (or 1597124 counting only the distinct ones).

The product of its digits is 13824, while the sum is 35.

The square root of 261921284 is about 16183.9823282158. The cubic root of 261921284 is about 639.8187019022.

The spelling of 261921284 in words is "two hundred sixty-one million, nine hundred twenty-one thousand, two hundred eighty-four".