61408804865 has 32 divisors (see below), whose sum is σ = 75278470176. Its totient is φ = 48080148480.

The previous prime is 61408804823. The next prime is 61408804939. The reversal of 61408804865 is 56840880416.

It is a Cunningham number, because it is equal to 247808²+1.

It can be written as a sum of positive squares in 16 ways, for example, as 362255089 + 61046549776 = 19033^2 + 247076^2 .

It is not a de Polignac number, because 61408804865 - 2⁸ = 61408804609 is a prime.

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 31 ways as a sum of consecutive naturals, for example, 44725319 + ... + 44726691.

It is an arithmetic number, because the mean of its divisors is an integer number (2352452193).

It is a Proth number, since it is equal to 14641 ⋅ 2²² + 1 and 14641 < 2²².

Almost surely, 2^61408804865 is an apocalyptic number.

It is an amenable number.

61408804865 is a deficient number, since it is larger than the sum of its proper divisors (13869665311).

61408804865 is a wasteful number, since it uses less digits than its factorization.

61408804865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2309.

The product of its (nonzero) digits is 1474560, while the sum is 50.

The spelling of 61408804865 in words is "sixty-one billion, four hundred eight million, eight hundred four thousand, eight hundred sixty-five".