61908561 has 36 divisors (see below), whose sum is σ = 105877044. Its totient is φ = 34626240.

The previous prime is 61908499. The next prime is 61908589. The reversal of 61908561 is 16580916.

61908561 is a `hidden beast` number, since 6 + 1 + 90 + 8 + 561 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 21344400 + 40564161 = 4620^2 + 6369^2 .

It is not a de Polignac number, because 61908561 - 2¹⁹ = 61384273 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (61908361) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 11971 + ... + 16343.

It is an arithmetic number, because the mean of its divisors is an integer number (2941029).

Almost surely, 2^61908561 is an apocalyptic number.

It is an amenable number.

61908561 is a deficient number, since it is larger than the sum of its proper divisors (43968483).

61908561 is a wasteful number, since it uses less digits than its factorization.

61908561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4414 (or 4400 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 61908561 is about 7868.1993492794. The cubic root of 61908561 is about 395.5944923055.

The spelling of 61908561 in words is "sixty-one million, nine hundred eight thousand, five hundred sixty-one".