261897479 has 4 divisors (see below), whose sum is σ = 263504376. Its totient is φ = 260290584.

The previous prime is 261897473. The next prime is 261897533. The reversal of 261897479 is 974798162.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261897479 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 261897479.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261897473) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 803204 + ... + 803529.

It is an arithmetic number, because the mean of its divisors is an integer number (65876094).

Almost surely, 2^261897479 is an apocalyptic number.

261897479 is a deficient number, since it is larger than the sum of its proper divisors (1606897).

261897479 is a wasteful number, since it uses less digits than its factorization.

261897479 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1606896.

The product of its digits is 1524096, while the sum is 53.

The square root of 261897479 is about 16183.2468621102. The cubic root of 261897479 is about 639.7993177761.

The spelling of 261897479 in words is "two hundred sixty-one million, eight hundred ninety-seven thousand, four hundred seventy-nine".