61721571071 has 4 divisors (see below), whose sum is σ = 61793592432. Its totient is φ = 61649549712.

The previous prime is 61721571059. The next prime is 61721571077. The reversal of 61721571071 is 17017512716.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 61721571071 - 2²² = 61717376767 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61721571077) 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, 36009395 + ... + 36011108.

It is an arithmetic number, because the mean of its divisors is an integer number (15448398108).

Almost surely, 2^61721571071 is an apocalyptic number.

61721571071 is a deficient number, since it is larger than the sum of its proper divisors (72021361).

61721571071 is an equidigital number, since it uses as much as digits as its factorization.

61721571071 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72021360.

The product of its (nonzero) digits is 20580, while the sum is 38.

The spelling of 61721571071 in words is "sixty-one billion, seven hundred twenty-one million, five hundred seventy-one thousand, seventy-one".