688821534 has 12 divisors (see below), whose sum is σ = 1492446696. Its totient is φ = 229607172.

The previous prime is 688821533. The next prime is 688821571. The reversal of 688821534 is 435128886.

It is a super-2 number, since 2×688821534² = 948950211404226312, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 688821534.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (688821533) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 19133914 + ... + 19133949.

It is an arithmetic number, because the mean of its divisors is an integer number (124370558).

Almost surely, 2^688821534 is an apocalyptic number.

688821534 is an abundant number, since it is smaller than the sum of its proper divisors (803625162).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

688821534 is a wasteful number, since it uses less digits than its factorization.

688821534 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38267871 (or 38267868 counting only the distinct ones).

The product of its digits is 368640, while the sum is 45.

The square root of 688821534 is about 26245.4097700912. The cubic root of 688821534 is about 883.1522340341.

The spelling of 688821534 in words is "six hundred eighty-eight million, eight hundred twenty-one thousand, five hundred thirty-four".