24778561 has 4 divisors (see below), whose sum is σ = 24800724. Its totient is φ = 24756400.

The previous prime is 24778549. The next prime is 24778573. The reversal of 24778561 is 16587742.

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

It is an interprime number because it is at equal distance from previous prime (24778549) and next prime (24778573).

It can be written as a sum of positive squares in 2 ways, for example, as 18326961 + 6451600 = 4281^2 + 2540^2 .

It is a cyclic number.

It is not a de Polignac number, because 24778561 - 2⁵ = 24778529 is a prime.

It is a super-2 number, since 2×24778561² = 1227954170461442, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (24778511) 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, 9310 + ... + 11671.

It is an arithmetic number, because the mean of its divisors is an integer number (6200181).

Almost surely, 2^24778561 is an apocalyptic number.

It is an amenable number.

24778561 is a deficient number, since it is larger than the sum of its proper divisors (22163).

24778561 is a wasteful number, since it uses less digits than its factorization.

24778561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22162.

The product of its digits is 94080, while the sum is 40.

The square root of 24778561 is about 4977.8068463933. The cubic root of 24778561 is about 291.5358901426.

The spelling of 24778561 in words is "twenty-four million, seven hundred seventy-eight thousand, five hundred sixty-one".