781538553061 has 12 divisors (see below), whose sum is σ = 913038571692. Its totient is φ = 667015113408.

The previous prime is 781538553023. The next prime is 781538553079. The reversal of 781538553061 is 160355835187.

It can be written as a sum of positive squares in 2 ways, for example, as 296718788961 + 484819764100 = 544719^2 + 696290^2 .

It is not a de Polignac number, because 781538553061 - 2²³ = 781530164453 is a prime.

It is a super-2 number, since 2×781538553061² (a number of 25 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 (781538553361) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 34215550 + ... + 34238383.

It is an arithmetic number, because the mean of its divisors is an integer number (76086547641).

Almost surely, 2^781538553061 is an apocalyptic number.

It is an amenable number.

781538553061 is a deficient number, since it is larger than the sum of its proper divisors (131500018631).

781538553061 is a wasteful number, since it uses less digits than its factorization.

781538553061 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68454180 (or 68454173 counting only the distinct ones).

The product of its (nonzero) digits is 3024000, while the sum is 52.

The spelling of 781538553061 in words is "seven hundred eighty-one billion, five hundred thirty-eight million, five hundred fifty-three thousand, sixty-one".