61172675561721 has 4 divisors (see below), whose sum is σ = 81563567415632. Its totient is φ = 40781783707812.

The previous prime is 61172675561713. The next prime is 61172675561741. The reversal of 61172675561721 is 12716557627116.

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 not a de Polignac number, because 61172675561721 - 2³ = 61172675561713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61172675561741) 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, 10195445926951 + ... + 10195445926956.

It is an arithmetic number, because the mean of its divisors is an integer number (20390891853908).

Almost surely, 2^{61172675561721} is an apocalyptic number.

It is an amenable number.

61172675561721 is a deficient number, since it is larger than the sum of its proper divisors (20390891853911).

61172675561721 is a wasteful number, since it uses less digits than its factorization.

61172675561721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20390891853910.

The product of its digits is 7408800, while the sum is 57.

The spelling of 61172675561721 in words is "sixty-one trillion, one hundred seventy-two billion, six hundred seventy-five million, five hundred sixty-one thousand, seven hundred twenty-one".