261974645 has 16 divisors (see below), whose sum is σ = 326246400. Its totient is φ = 201734400.

The previous prime is 261974639. The next prime is 261974651. The reversal of 261974645 is 546479162.

It is an interprime number because it is at equal distance from previous prime (261974639) and next prime (261974651).

It is a de Polignac number, because none of the positive numbers 2^k-261974645 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 261974596 and 261974605.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25181 + ... + 34029.

It is an arithmetic number, because the mean of its divisors is an integer number (20390400).

Almost surely, 2^261974645 is an apocalyptic number.

It is an amenable number.

261974645 is a deficient number, since it is larger than the sum of its proper divisors (64271755).

261974645 is a wasteful number, since it uses less digits than its factorization.

261974645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9076.

The product of its digits is 362880, while the sum is 44.

The square root of 261974645 is about 16185.6308187231. The cubic root of 261974645 is about 639.8621488582.

The spelling of 261974645 in words is "two hundred sixty-one million, nine hundred seventy-four thousand, six hundred forty-five".