61215555501 has 12 divisors (see below), whose sum is σ = 90812266012. Its totient is φ = 39707387136.

The previous prime is 61215555491. The next prime is 61215555521. The reversal of 61215555501 is 10555551216.

It can be written as a sum of positive squares in 2 ways, for example, as 23947253001 + 37268302500 = 154749^2 + 193050^2 .

It is not a de Polignac number, because 61215555501 - 2⁶ = 61215555437 is a prime.

It is a super-2 number, since 2×61215555501² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61215555521) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 91914916 + ... + 91915581.

Almost surely, 2^61215555501 is an apocalyptic number.

It is an amenable number.

61215555501 is a deficient number, since it is larger than the sum of its proper divisors (29596710511).

61215555501 is a wasteful number, since it uses less digits than its factorization.

61215555501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 183830540 (or 183830537 counting only the distinct ones).

The product of its (nonzero) digits is 37500, while the sum is 36.

The spelling of 61215555501 in words is "sixty-one billion, two hundred fifteen million, five hundred fifty-five thousand, five hundred one".