61621066155665 has 16 divisors (see below), whose sum is σ = 75750149704320. Its totient is φ = 48093648170880.

The previous prime is 61621066155643. The next prime is 61621066155679. The reversal of 61621066155665 is 56655166012616.

It is not a de Polignac number, because 61621066155665 - 2¹⁸ = 61621065893521 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 61621066155665.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9228482 + ... + 14436308.

It is an arithmetic number, because the mean of its divisors is an integer number (4734384356520).

Almost surely, 2^{61621066155665} is an apocalyptic number.

It is an amenable number.

61621066155665 is a deficient number, since it is larger than the sum of its proper divisors (14129083548655).

61621066155665 is a wasteful number, since it uses less digits than its factorization.

61621066155665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5265592.

The product of its (nonzero) digits is 11664000, while the sum is 56.

The spelling of 61621066155665 in words is "sixty-one trillion, six hundred twenty-one billion, sixty-six million, one hundred fifty-five thousand, six hundred sixty-five".