621381 has 4 divisors (see below), whose sum is σ = 828512. Its totient is φ = 414252.

The previous prime is 621371. The next prime is 621389. The reversal of 621381 is 183126.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 621381 - 2⁶ = 621317 is a prime.

It is a super-2 number, since 2×621381² = 772228694322, which contains 22 as substring.

It is a D-number.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (621389) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 103561 + ... + 103566.

It is an arithmetic number, because the mean of its divisors is an integer number (207128).

2⁶²¹³⁸¹ is an apocalyptic number.

It is an amenable number.

621381 is a deficient number, since it is larger than the sum of its proper divisors (207131).

621381 is a wasteful number, since it uses less digits than its factorization.

621381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 207130.

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

The square root of 621381 is about 788.2772354952. The cubic root of 621381 is about 85.3334537081. Note that the first 3 decimals are identical.

The spelling of 621381 in words is "six hundred twenty-one thousand, three hundred eighty-one".