971212517721 has 12 divisors (see below), whose sum is σ = 1403021174100. Its totient is φ = 647401789440.

The previous prime is 971212517699. The next prime is 971212517729. The reversal of 971212517721 is 127715212179.

971212517721 is a `hidden beast` number, since 9 + 7 + 121 + 2 + 517 + 7 + 2 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 214312517721 + 756900000000 = 462939^2 + 870000^2 .

It is not a de Polignac number, because 971212517721 - 2⁶ = 971212517657 is a prime.

It is not an unprimeable number, because it can be changed into a prime (971212517729) 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, 6017800 + ... + 6177081.

It is an arithmetic number, because the mean of its divisors is an integer number (116918431175).

Almost surely, 2^971212517721 is an apocalyptic number.

It is an amenable number.

971212517721 is a deficient number, since it is larger than the sum of its proper divisors (431808656379).

971212517721 is a wasteful number, since it uses less digits than its factorization.

971212517721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12203736 (or 12203733 counting only the distinct ones).

The product of its digits is 123480, while the sum is 45.

The spelling of 971212517721 in words is "nine hundred seventy-one billion, two hundred twelve million, five hundred seventeen thousand, seven hundred twenty-one".