687721498 has 4 divisors (see below), whose sum is σ = 1031582250. Its totient is φ = 343860748.

The previous prime is 687721487. The next prime is 687721499. The reversal of 687721498 is 894127786.

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

It can be written as a sum of positive squares in only one way, i.e., 370062169 + 317659329 = 19237^2 + 17823^2 .

It is a super-2 number, since 2×687721498² = 945921717622728008, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (687721499) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 171930373 + ... + 171930376.

Almost surely, 2^687721498 is an apocalyptic number.

687721498 is a deficient number, since it is larger than the sum of its proper divisors (343860752).

687721498 is a wasteful number, since it uses less digits than its factorization.

687721498 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 343860751.

The product of its digits is 1354752, while the sum is 52.

The square root of 687721498 is about 26224.4446652355. Note that the first 3 decimals coincide. The cubic root of 687721498 is about 882.6818573022.

The spelling of 687721498 in words is "six hundred eighty-seven million, seven hundred twenty-one thousand, four hundred ninety-eight".