621994 has 4 divisors (see below), whose sum is σ = 932994. Its totient is φ = 310996.

The previous prime is 621983. The next prime is 621997. The reversal of 621994 is 499126.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 499126 = 2 ⋅249563.

It can be written as a sum of positive squares in only one way, i.e., 405769 + 216225 = 637^2 + 465^2 .

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (621997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 155497 + ... + 155500.

2⁶²¹⁹⁹⁴ is an apocalyptic number.

621994 is a deficient number, since it is larger than the sum of its proper divisors (311000).

621994 is a wasteful number, since it uses less digits than its factorization.

621994 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 310999.

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

The square root of 621994 is about 788.6659622426. The cubic root of 621994 is about 85.3615053196.

The spelling of 621994 in words is "six hundred twenty-one thousand, nine hundred ninety-four".