61661855 has 8 divisors (see below), whose sum is σ = 74042592. Its totient is φ = 49297248.

The previous prime is 61661777. The next prime is 61661857. The reversal of 61661855 is 55816616.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 61661855 - 2¹⁴ = 61645471 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61661857) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7262 + ... + 13268.

It is an arithmetic number, because the mean of its divisors is an integer number (9255324).

Almost surely, 2^61661855 is an apocalyptic number.

61661855 is a deficient number, since it is larger than the sum of its proper divisors (12380737).

61661855 is a wasteful number, since it uses less digits than its factorization.

61661855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8065.

The product of its digits is 43200, while the sum is 38.

The square root of 61661855 is about 7852.5062878039. The cubic root of 61661855 is about 395.0683105700.

The spelling of 61661855 in words is "sixty-one million, six hundred sixty-one thousand, eight hundred fifty-five".