921618 has 20 divisors (see below), whose sum is σ = 2065470. Its totient is φ = 307152.

The previous prime is 921611. The next prime is 921629. The reversal of 921618 is 816129.

It can be written as a sum of positive squares in only one way, i.e., 558009 + 363609 = 747^2 + 603^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an alternating number because its digits alternate between odd and even.

It is a junction number, because it is equal to n+sod(n) for n = 921591 and 921600.

It is not an unprimeable number, because it can be changed into a prime (921611) by changing a digit.

921618 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 2683 + ... + 3006.

2⁹²¹⁶¹⁸ is an apocalyptic number.

921618 is an abundant number, since it is smaller than the sum of its proper divisors (1143852).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

921618 is a wasteful number, since it uses less digits than its factorization.

921618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5703 (or 5694 counting only the distinct ones).

The product of its digits is 864, while the sum is 27.

The square root of 921618 is about 960.0093749542. The cubic root of 921618 is about 97.3158654878.

The spelling of 921618 in words is "nine hundred twenty-one thousand, six hundred eighteen".