61780905 has 24 divisors (see below), whose sum is σ = 107290248. Its totient is φ = 32887296.

The previous prime is 61780883. The next prime is 61780919. The reversal of 61780905 is 50908716.

It can be written as a sum of positive squares in 4 ways, for example, as 6471936 + 55308969 = 2544^2 + 7437^2 .

It is not a de Polignac number, because 61780905 - 2⁶ = 61780841 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 61780905.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 32049 + ... + 33921.

It is an arithmetic number, because the mean of its divisors is an integer number (4470427).

Almost surely, 2^61780905 is an apocalyptic number.

It is an amenable number.

61780905 is a deficient number, since it is larger than the sum of its proper divisors (45509343).

61780905 is a wasteful number, since it uses less digits than its factorization.

61780905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2617 (or 2614 counting only the distinct ones).

The product of its (nonzero) digits is 15120, while the sum is 36.

The square root of 61780905 is about 7860.0830148288. The cubic root of 61780905 is about 395.3223987533.

The spelling of 61780905 in words is "sixty-one million, seven hundred eighty thousand, nine hundred five".