621138 has 32 divisors (see below), whose sum is σ = 1483776. Its totient is φ = 169488.

The previous prime is 621133. The next prime is 621139. The reversal of 621138 is 831126.

621138 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is not an unprimeable number, because it can be changed into a prime (621133) 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, 645 + ... + 1287.

It is an arithmetic number, because the mean of its divisors is an integer number (46368).

2⁶²¹¹³⁸ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 621138, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (741888).

621138 is an abundant number, since it is smaller than the sum of its proper divisors (862638).

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

621138 is a wasteful number, since it uses less digits than its factorization.

621138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 678.

The product of its digits is 288, while the sum is 21.

The square root of 621138 is about 788.1230868335. The cubic root of 621138 is about 85.3223286319.

The spelling of 621138 in words is "six hundred twenty-one thousand, one hundred thirty-eight".