688401647 has 4 divisors (see below), whose sum is σ = 688569336. Its totient is φ = 688233960.

The previous prime is 688401641. The next prime is 688401667. The reversal of 688401647 is 746104886.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 688401647 - 2¹⁴ = 688385263 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 688401598 and 688401607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (688401641) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 77528 + ... + 85949.

It is an arithmetic number, because the mean of its divisors is an integer number (172142334).

Almost surely, 2^688401647 is an apocalyptic number.

688401647 is a deficient number, since it is larger than the sum of its proper divisors (167689).

688401647 is a wasteful number, since it uses less digits than its factorization.

688401647 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 167688.

The product of its (nonzero) digits is 258048, while the sum is 44.

The square root of 688401647 is about 26237.4093042739. The cubic root of 688401647 is about 882.9727489776.

The spelling of 688401647 in words is "six hundred eighty-eight million, four hundred one thousand, six hundred forty-seven".