61404665681 has 4 divisors (see below), whose sum is σ = 61437913152. Its totient is φ = 61371418212.

The previous prime is 61404665551. The next prime is 61404665689. The reversal of 61404665681 is 18656640416.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 61404665681 - 2¹⁴ = 61404649297 is a prime.

It is a super-2 number, since 2×61404665681² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61404665689) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16620965 + ... + 16624658.

It is an arithmetic number, because the mean of its divisors is an integer number (15359478288).

Almost surely, 2^61404665681 is an apocalyptic number.

It is an amenable number.

61404665681 is a deficient number, since it is larger than the sum of its proper divisors (33247471).

61404665681 is a wasteful number, since it uses less digits than its factorization.

61404665681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33247470.

The product of its (nonzero) digits is 829440, while the sum is 47.

The spelling of 61404665681 in words is "sixty-one billion, four hundred four million, six hundred sixty-five thousand, six hundred eighty-one".