61638305 has 4 divisors (see below), whose sum is σ = 73965972. Its totient is φ = 49310640.

The previous prime is 61638289. The next prime is 61638331. The reversal of 61638305 is 50383616.

61638305 = 5551² + 5552².

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

It can be written as a sum of positive squares in 2 ways, for example, as 30824704 + 30813601 = 5552^2 + 5551^2 .

It is not a de Polignac number, because 61638305 - 2⁴ = 61638289 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6163826 + ... + 6163835.

It is an arithmetic number, because the mean of its divisors is an integer number (18491493).

Almost surely, 2^61638305 is an apocalyptic number.

61638305 is the 5552-nd centered square number.

It is an amenable number.

61638305 is a deficient number, since it is larger than the sum of its proper divisors (12327667).

61638305 is a wasteful number, since it uses less digits than its factorization.

61638305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12327666.

The product of its (nonzero) digits is 12960, while the sum is 32.

The square root of 61638305 is about 7851.0066233573. The cubic root of 61638305 is about 395.0180091132.

The spelling of 61638305 in words is "sixty-one million, six hundred thirty-eight thousand, three hundred five".