921649 has 8 divisors (see below), whose sum is σ = 970920. Its totient is φ = 873600.

The previous prime is 921647. The next prime is 921667. The reversal of 921649 is 946129.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 49 + 921600 = 7^2 + 960^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 921649 - 2¹ = 921647 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 921649.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (921643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1509 + ... + 2029.

It is an arithmetic number, because the mean of its divisors is an integer number (121365).

2⁹²¹⁶⁴⁹ is an apocalyptic number.

It is an amenable number.

921649 is a deficient number, since it is larger than the sum of its proper divisors (49271).

921649 is a wasteful number, since it uses less digits than its factorization.

921649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 611.

The product of its digits is 3888, while the sum is 31.

The square root of 921649 is about 960.0255204941. The cubic root of 921649 is about 97.3169565971.

It can be divided in two parts, 9216 and 49, that multiplied together give a square (451584 = 672²).

The spelling of 921649 in words is "nine hundred twenty-one thousand, six hundred forty-nine".