8261057805781 has 32 divisors (see below), whose sum is σ = 9098220246912. Its totient is φ = 7438519695360.

The previous prime is 8261057805731. The next prime is 8261057805809. The reversal of 8261057805781 is 1875087501628.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8261057805781 is a prime.

It is a super-2 number, since 2×8261057805781² (a number of 27 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 (8261057805701) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1904784045 + ... + 1904788381.

It is an arithmetic number, because the mean of its divisors is an integer number (284319382716).

Almost surely, 2^{8261057805781} is an apocalyptic number.

It is an amenable number.

8261057805781 is a deficient number, since it is larger than the sum of its proper divisors (837162441131).

8261057805781 is a wasteful number, since it uses less digits than its factorization.

8261057805781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7029.

The product of its (nonzero) digits is 7526400, while the sum is 58.

The spelling of 8261057805781 in words is "eight trillion, two hundred sixty-one billion, fifty-seven million, eight hundred five thousand, seven hundred eighty-one".