688993551 has 6 divisors (see below), whose sum is σ = 995212920. Its totient is φ = 459329028.

The previous prime is 688993549. The next prime is 688993567. The reversal of 688993551 is 155399886.

It is a happy number.

688993551 is a `hidden beast` number, since 6 + 8 + 89 + 9 + 3 + 551 = 666.

It is not a de Polignac number, because 688993551 - 2¹ = 688993549 is a prime.

It is a super-2 number, since 2×688993551² = 949424226639179202, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (688993531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 38277411 + ... + 38277428.

It is an arithmetic number, because the mean of its divisors is an integer number (165868820).

Almost surely, 2^688993551 is an apocalyptic number.

688993551 is a deficient number, since it is larger than the sum of its proper divisors (306219369).

688993551 is a wasteful number, since it uses less digits than its factorization.

688993551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76554845 (or 76554842 counting only the distinct ones).

The product of its digits is 2332800, while the sum is 54.

The square root of 688993551 is about 26248.6866528594. The cubic root of 688993551 is about 883.2257434247.

The spelling of 688993551 in words is "six hundred eighty-eight million, nine hundred ninety-three thousand, five hundred fifty-one".