687941021 has 8 divisors (see below), whose sum is σ = 705074304. Its totient is φ = 670911840.

The previous prime is 687940993. The next prime is 687941027. The reversal of 687941021 is 120149786.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 687941021 - 2¹⁸ = 687678877 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (687941027) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12560 + ... + 39161.

It is an arithmetic number, because the mean of its divisors is an integer number (88134288).

Almost surely, 2^687941021 is an apocalyptic number.

It is an amenable number.

687941021 is a deficient number, since it is larger than the sum of its proper divisors (17133283).

687941021 is a wasteful number, since it uses less digits than its factorization.

687941021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52051.

The product of its (nonzero) digits is 24192, while the sum is 38.

The square root of 687941021 is about 26228.6297964648. The cubic root of 687941021 is about 882.7757656436.

The spelling of 687941021 in words is "six hundred eighty-seven million, nine hundred forty-one thousand, twenty-one".