618921 has 16 divisors (see below), whose sum is σ = 931520. Its totient is φ = 411156.

The previous prime is 618913. The next prime is 618929. The reversal of 618921 is 129816.

618921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (618913) and next prime (618929).

It is not a de Polignac number, because 618921 - 2³ = 618913 is a prime.

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 even and odd.

It is a Duffinian number.

It is a Curzon number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 618921.

It is not an unprimeable number, because it can be changed into a prime (618929) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2046 + ... + 2328.

It is an arithmetic number, because the mean of its divisors is an integer number (58220).

2⁶¹⁸⁹²¹ is an apocalyptic number.

It is an amenable number.

618921 is a deficient number, since it is larger than the sum of its proper divisors (312599).

618921 is an frugal number, since it uses more digits than its factorization.

618921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 304 (or 286 counting only the distinct ones).

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

The square root of 618921 is about 786.7153233540. The cubic root of 618921 is about 85.2206952306.

It can be divided in two parts, 6 and 18921, that multiplied together give a triangular number (113526 = T₄₇₆).

The spelling of 618921 in words is "six hundred eighteen thousand, nine hundred twenty-one".