691281253125 has 96 divisors (see below), whose sum is σ = 1355369500800. Its totient is φ = 346995360000.

The previous prime is 691281253109. The next prime is 691281253127. The reversal of 691281253125 is 521352182196.

691281253125 is a `hidden beast` number, since 6 + 9 + 12 + 81 + 2 + 531 + 25 = 666.

It is not a de Polignac number, because 691281253125 - 2⁴ = 691281253109 is a prime.

It is a super-4 number, since 4×691281253125⁴ (a number of 48 digits) contains 4444 as substring. Note that it is a super-d number also for d = 3.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (691281253127) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1193406 + ... + 1675344.

It is an arithmetic number, because the mean of its divisors is an integer number (14118432300).

Almost surely, 2^691281253125 is an apocalyptic number.

It is an amenable number.

691281253125 is a deficient number, since it is larger than the sum of its proper divisors (664088247675).

691281253125 is an equidigital number, since it uses as much as digits as its factorization.

691281253125 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 481990 (or 481964 counting only the distinct ones).

The product of its digits is 259200, while the sum is 45.

The spelling of 691281253125 in words is "six hundred ninety-one billion, two hundred eighty-one million, two hundred fifty-three thousand, one hundred twenty-five".