688878421 has 16 divisors (see below), whose sum is σ = 904066560. Its totient is φ = 508535280.

The previous prime is 688878413. The next prime is 688878431. The reversal of 688878421 is 124878886.

It is a happy number.

It is not a de Polignac number, because 688878421 - 2³ = 688878413 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (688878431) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 233971 + ... + 236896.

It is an arithmetic number, because the mean of its divisors is an integer number (56504160).

Almost surely, 2^688878421 is an apocalyptic number.

It is an amenable number.

688878421 is a deficient number, since it is larger than the sum of its proper divisors (215188139).

688878421 is a wasteful number, since it uses less digits than its factorization.

688878421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 470904.

The product of its digits is 1376256, while the sum is 52.

The square root of 688878421 is about 26246.4934991324. The cubic root of 688878421 is about 883.1765453618.

The spelling of 688878421 in words is "six hundred eighty-eight million, eight hundred seventy-eight thousand, four hundred twenty-one".