71220787561 has 16 divisors (see below), whose sum is σ = 89339516928. Its totient is φ = 55156237200.

The previous prime is 71220787489. The next prime is 71220787577. The reversal of 71220787561 is 16578702217.

It is a cyclic number.

It is not a de Polignac number, because 71220787561 - 2⁷ = 71220787433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (71220707561) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2824705 + ... + 2849806.

It is an arithmetic number, because the mean of its divisors is an integer number (5583719808).

Almost surely, 2^71220787561 is an apocalyptic number.

It is an amenable number.

71220787561 is a deficient number, since it is larger than the sum of its proper divisors (18118729367).

71220787561 is a wasteful number, since it uses less digits than its factorization.

71220787561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5674692.

The product of its (nonzero) digits is 329280, while the sum is 46.

The spelling of 71220787561 in words is "seventy-one billion, two hundred twenty million, seven hundred eighty-seven thousand, five hundred sixty-one".