909685921 has 3 divisors (see below), whose sum is σ = 909716083. Its totient is φ = 909655760.

The previous prime is 909685919. The next prime is 909685937. The reversal of 909685921 is 129586909.

The square root of 909685921 is 30161.

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, and also an emirpimes, since its reverse is a distinct semiprime: 129586909 = 2377 ⋅54517.

It can be written as a sum of positive squares in only one way, i.e., 726895521 + 182790400 = 26961^2 + 13520^2 .

It is not a de Polignac number, because 909685921 - 2¹ = 909685919 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (909685951) 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, 15081 + ... + 45241.

Almost surely, 2^909685921 is an apocalyptic number.

909685921 is the 30161-st square number.

909685921 is the 15081-st centered octagonal number.

It is an amenable number.

909685921 is a deficient number, since it is larger than the sum of its proper divisors (30162).

909685921 is an frugal number, since it uses more digits than its factorization.

909685921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60322 (or 30161 counting only the distinct ones).

The product of its (nonzero) digits is 349920, while the sum is 49.

The cubic root of 909685921 is about 968.9406087318.

Multiplying 909685921 by its sum of digits (49), we get a square (44574610129 = 211127²).

The spelling of 909685921 in words is "nine hundred nine million, six hundred eighty-five thousand, nine hundred twenty-one".