261921445 has 8 divisors (see below), whose sum is σ = 318611736. Its totient is φ = 206666496.

The previous prime is 261921427. The next prime is 261921463. The reversal of 261921445 is 544129162.

It is an interprime number because it is at equal distance from previous prime (261921427) and next prime (261921463).

It can be written as a sum of positive squares in 4 ways, for example, as 22724289 + 239197156 = 4767^2 + 15466^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 261921445 - 2¹¹ = 261919397 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 261921445.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 358432 + ... + 359161.

It is an arithmetic number, because the mean of its divisors is an integer number (39826467).

Almost surely, 2^261921445 is an apocalyptic number.

It is an amenable number.

261921445 is a deficient number, since it is larger than the sum of its proper divisors (56690291).

261921445 is an equidigital number, since it uses as much as digits as its factorization.

261921445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 717671.

The product of its digits is 17280, while the sum is 34.

The square root of 261921445 is about 16183.9873022689. The cubic root of 261921445 is about 639.8188329986.

The spelling of 261921445 in words is "two hundred sixty-one million, nine hundred twenty-one thousand, four hundred forty-five".