71115561621 has 12 divisors (see below), whose sum is σ = 110624207148. Its totient is φ = 43763422464.

The previous prime is 71115561599. The next prime is 71115561641. The reversal of 71115561621 is 12616551117.

71115561621 is a `hidden beast` number, since 7 + 1 + 1 + 15 + 5 + 616 + 21 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 23998347396 + 47117214225 = 154914^2 + 217065^2 .

It is not a de Polignac number, because 71115561621 - 2⁶ = 71115561557 is a prime.

It is a super-3 number, since 3×71115561621³ (a number of 34 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71115561641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 303912540 + ... + 303912773.

It is an arithmetic number, because the mean of its divisors is an integer number (9218683929).

Almost surely, 2^71115561621 is an apocalyptic number.

It is an amenable number.

71115561621 is a deficient number, since it is larger than the sum of its proper divisors (39508645527).

71115561621 is a wasteful number, since it uses less digits than its factorization.

71115561621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 607825332 (or 607825329 counting only the distinct ones).

The product of its digits is 12600, while the sum is 36.

The spelling of 71115561621 in words is "seventy-one billion, one hundred fifteen million, five hundred sixty-one thousand, six hundred twenty-one".