6461156777561 has 4 divisors (see below), whose sum is σ = 6635782636452. Its totient is φ = 6286530918672.

The previous prime is 6461156777531. The next prime is 6461156777633. The reversal of 6461156777561 is 1657776511646.

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

It can be written as a sum of positive squares in 2 ways, for example, as 5391289267225 + 1069867510336 = 2321915^2 + 1034344^2 .

It is a cyclic number.

It is not a de Polignac number, because 6461156777561 - 2⁶ = 6461156777497 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 6461156777494 and 6461156777503.

It is not an unprimeable number, because it can be changed into a prime (6461156777521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 87312929390 + ... + 87312929463.

It is an arithmetic number, because the mean of its divisors is an integer number (1658945659113).

Almost surely, 2^{6461156777561} is an apocalyptic number.

It is an amenable number.

6461156777561 is a deficient number, since it is larger than the sum of its proper divisors (174625858891).

6461156777561 is a wasteful number, since it uses less digits than its factorization.

6461156777561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 174625858890.

The product of its digits is 44452800, while the sum is 62.

The spelling of 6461156777561 in words is "six trillion, four hundred sixty-one billion, one hundred fifty-six million, seven hundred seventy-seven thousand, five hundred sixty-one".