8688705370921 has 3 divisors (see below), whose sum is σ = 8688708318583. Its totient is φ = 8688702423260.

The previous prime is 8688705370889. The next prime is 8688705370979. The reversal of 8688705370921 is 1290735078868.

It is a happy number.

The square root of 8688705370921 is 2947661.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 3805577722521 + 4883127648400 = 1950789^2 + 2209780^2 .

It is not a de Polignac number, because 8688705370921 - 2⁵ = 8688705370889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8688705377921) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 1473831 + ... + 4421491.

Almost surely, 2^{8688705370921} is an apocalyptic number.

8688705370921 is the 2947661-st square number.

8688705370921 is the 1473831-st centered octagonal number.

It is an amenable number.

8688705370921 is a deficient number, since it is larger than the sum of its proper divisors (2947662).

8688705370921 is an frugal number, since it uses more digits than its factorization.

8688705370921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5895322 (or 2947661 counting only the distinct ones).

The product of its (nonzero) digits is 40642560, while the sum is 64.

Multiplying 8688705370921 by its sum of digits (64), we get a square (556077143738944 = 23581288²).

The spelling of 8688705370921 in words is "eight trillion, six hundred eighty-eight billion, seven hundred five million, three hundred seventy thousand, nine hundred twenty-one".